Contents

1. Introduction
2. Unboxing and Initial Setup
3. Reading the Screen and Basic Operation
4. Pairing with a Companion Wallet
5. Receiving Crypto Assets
6. Sending Crypto Assets
7. Choosing and Configuring the Connection Method
8. Security and Backup
9. Using It as a Security Key (FIDO2 / Passkeys)
10. Using It as a PKCS#11 Signer (PIV)
11. Screen Map
12. Firmware Update (OTA)
13. Troubleshooting
14. Supported Crypto Assets and Networks
15. Appendix

1. Introduction

1.1 What is Openloop?

Openloop is a hardware wallet for crypto assets, a FIDO2 security key, and a PKCS#11 signer all in one. It keeps your private keys safe and signs in an environment completely isolated from the internet.

Three ways to use it:

• 🔐 Hardware wallet: private key management and signing for crypto assets (Bitcoin / Ethereum / XRP / Solana / TRON)
• 🔑 FIDO2 security key (passkeys): passwordless authentication to web services and apps from a PC or smartphone (USB on PC, BLE on mobile — Openloop Connect required)
• 📝 PKCS#11 signer (PIV): SSH authentication, PDF signing, GPG signing, TLS client authentication (over USB, with Openloop Connect)

Key features:

• Encrypted storage: private keys protected with AES-256-GCM
• Touchscreen: an intuitive 320×240 pixel display
• Three connection methods: Air Gap (QR code) / USB / Bluetooth USB and Bluetooth are the standard methods for everyday use; Air Gap is the option for operating without any electronic communication
• Multi-currency support: Bitcoin / Ethereum (215 networks) / XRP / Solana / TRON
• FIDO2/CTAP2: passkey support (ES256 / EdDSA)
• PIV/PKCS#11: SSH / PDF signing / TLS authentication (P-256 / Ed25519 / RSA-2048)
• Multilingual: Japanese / English

★ Secure element: an NXP SE050 secure element (EAL6+ certified) protects your private keys in hardware.

1.2 How to Use This Manual

• ℹ Tip: handy techniques and supplementary information
• ▲ Warning: important cautions and security-related information
• Checkpoint: items you should verify

Suggested reading order:

1. First time: Ch. 1 → 2 → 3 → 4 → 7
2. To send funds: Ch. 5 → 6
3. To use it as a security key: Ch. 9
4. To use it as a PKCS#11 signer: Ch. 10
5. To change settings: Ch. 11
6. When you run into trouble: Ch. 13

1.3 Important Safety Information

▲ Your recovery phrase is your most important asset

Why the recovery phrase (12 or 24 words) matters:

• With it, you can restore your assets even if you lose the device
• Lose it and your assets are gone forever (nobody can help you)
• If it is stolen, your assets will be stolen (you cannot get them back)

Things you must not do casually:

• ✗ Photograph it with your phone and store it in the cloud (the cloud can be hacked)
• ✗ Type it into a computer (malware can steal it)
• ✗ Show or tell it to anyone (be careful)
• ✗ Save it in online storage
• ✗ Send it by email or messaging

Things you must do:

• ✓ Write it down on paper by hand
• ✓ Make several copies (2–3)
• ✓ Store them separately, for example in a fireproof safe
• ✓ Tell your family where they are (for inheritance)

▲ Managing your PIN

• PIN: required to unlock the device (4–6 digits)
• Get it wrong 10 times: ▲ the device automatically erases all data (see below)
• If you forget it: you will need to restore from your recovery phrase

▲ Getting the PIN wrong 10 times in a row makes the device automatically perform a factory reset. In addition to your wallet (recovery phrase), PIN, and all settings, your FIDO2 passkeys and PIV keys and certificates are also completely erased and can never be recovered. Crypto assets can be restored from your recovery phrase, but passkeys must be registered again at each service, and PIV keys must be regenerated with new certificates issued. After nine failures, wait for the lockout to clear and then enter the correct PIN calmly.

▲ Beware of phishing

• Use official software only: trusted applications such as Sparrow Wallet and MetaMask
• Suspicious emails and DMs: messages like “please verify your wallet” are scams
• Support scams: official support will never ask you for your private key or recovery phrase

1.4 Terms of Use and Disclaimer

Please read the following terms of use and disclaimer before using this product. By using this product, you are deemed to have agreed to them.

Software license

The Openloop firmware and software are provided “AS IS.”

• No warranty: the software is provided without warranty
• Copyright: all software copyrights belong to the manufacturer

Your responsibilities

What you are responsible for:

• Storing your recovery phrase safely
• Managing your PIN appropriately
• Verifying transaction details (destination address, amount, fee)
• Physically protecting the device (preventing theft and loss)
• Updating the firmware regularly
• Creating and storing backups

The manufacturer and developers accept no responsibility whatsoever for:

1. Losses relating to crypto assets
   • Losses from price volatility
   • Loss of assets due to a lost or stolen recovery phrase
   • Device lockout due to a forgotten PIN
   • User error (sending to the wrong address, mistyping an address)
   • Damage from fraud or phishing
   • Blockchain network failures or delays
   • Failures or bankruptcy of exchanges or third-party services
2. Technical problems
   • Losses caused by software bugs
   • Hardware compatibility problems
   • Interoperability problems with third-party wallet software
   • Trouble during firmware updates
   • Connection errors on any transport (QR / USB / BLE)
3. Legal and regulatory matters
   • Changes to laws and regulations in any country
   • Changes to the legal status of crypto assets
   • Tax matters (calculating and filing taxes is your responsibility)
   • Compliance with anti-money-laundering law
4. Other
   • Damage to the device from natural disasters or accidents
   • Unauthorized access or hacking by third parties
   • Loss or corruption of data
   • Errors or omissions in this manual

Important points to understand

▲ Crypto assets are extremely high-risk:

• Prices can move dramatically
• Once sent, a transaction cannot be reversed
• Losing your private key means losing your assets forever
• No government or company will compensate you

▲ Openloop is a signing-only device:

• It does not connect to the internet (air gap)
• It cannot check the state of the blockchain
• It has no balance display (check with third-party wallet software)
• Broadcasting a transaction is done by third-party wallet software

Before you use it, always:

• Back up your recovery phrase in several places
• Test with a small transfer first
• Verify the details (address, amount, fee) on the device screen
• Use only wallet software you trust

1.5 Warranty

Hardware warranty

Warranty period: 6 months from the date of purchase

Covered:

• Failures caused by manufacturing defects
• Component failures under normal use
• Touchscreen malfunctions (manufacturing defects only)
• USB/BLE communication failures (manufacturing defects only)

Not covered:

• Damage caused by the user (drops, water damage, disassembly, and so on)
• Failures caused by improper use or storage
• Problems caused by modification or repair
• Natural battery degradation
• Minor scratches or marks on the screen
• Software and firmware defects
• Compatibility problems with third-party products

Scope of the warranty:

• Covered failures will be repaired or replaced free of charge
• Loss of crypto assets is not covered
• We do not offer data recovery or migration services
• Shipping in both directions is at your expense

Software warranty

▲ The software is provided without warranty (AS IS)

• Firmware and software are provided “as is”
• Losses caused by bugs or defects are not covered
• We carry out ongoing security review and improvement
• Security updates are provided on a best-effort basis

Asset guarantee

There is no guarantee of any kind regarding crypto assets

• Even when the device works correctly, asset losses are not compensated
• Loss of assets due to a lost recovery phrase is not covered
• User error (sending to the wrong place) is not covered
• Losses caused by software bugs are not covered
• Problems with third-party services (exchanges, wallet software) are not covered

How to make a warranty claim

If a failure or defect occurs:

1. Prepare proof of purchase: have your receipt ready
2. Describe the symptoms: note the specifics (steps to reproduce, error messages, and so on)
3. Contact support: get in touch through the official support channel
4. Diagnosis: the support team determines whether it is covered
5. Repair or replacement: handled free of charge if covered

▲ Important: when a device is repaired or replaced, all data on it is erased. Make sure you can restore from your recovery phrase first.

Acknowledgement of the disclaimer

By using this product, you are deemed to understand and agree that:

• Managing crypto assets is entirely at your own risk
• Losing your recovery phrase means permanently losing your assets
• The manufacturer and developers accept no responsibility whatsoever for asset losses
• The hardware warranty covers physical device failures only
• The software is provided without warranty (AS IS)

1.6 Privacy Policy

Openloop respects your privacy and keeps data collection to an absolute minimum.

Basic principles

Openloop is an offline device

• It does not connect to the internet
• It does not send user data to any server
• It does not track how you use it
• It collects no data for advertising or marketing

Data stored on the device

The following data is stored only on the device and is never transmitted:

★ Secure element: the device carries an NXP SE050 secure element (EAL6+ certified). Private keys are protected by the dual-secure mechanism and stored safely inside the secure element.

▲ Important: running “Erase Wallet” or “Factory Reset” completely deletes the private keys, entropy, and seed. Without a backup of your recovery phrase, your assets are lost forever. A factory reset also deletes your FIDO2 passkeys and PIV keys.

Data in transit

Air Gap (QR code):

• The only data is what appears on screen as a QR code
• No network communication
• The most private method

USB:

• A direct connection to your PC
• Data travels over the USB cable only
• Nothing is sent over the internet
• Security depends on the PC you connect to

Bluetooth Low Energy (BLE):

• Encrypted communication with paired devices
• A range of about 10 m
• Pairing data is stored on the device
• Connection history is never transmitted

Sharing data with third parties

We never provide user data to third parties

• No data sold to advertisers
• No data sent to analytics services
• No voluntary disclosure to government agencies
• No data shared with business partners

▲ Exception: if we receive a legally binding request (such as a court order), we may respond within the limits of the law. Because Openloop is an offline device, however, the manufacturer has no means of accessing user data.

Privacy of companion wallets

The wallet software you pair with Openloop (Sparrow Wallet, MetaMask, and so on) each has its own privacy policy.

• Sparrow Wallet: open source, privacy-focused
• MetaMask: governed by ConsenSys’s privacy policy
• Other software: check each application’s policy

ℹ Tip: for maximum privacy, we recommend combining QR-code communication, your own node, and Sparrow Wallet.

Deleting your data

To completely delete your data:

1. Settings → Security → Factory Reset
2. Choose “Yes” on the confirmation screen
3. All data is completely deleted

▲ Warning: this cannot be undone. Make sure you have a backup of your recovery phrase first.

1.7 Export Controls and Compliance

Openloop contains cryptographic technology and may be subject to import/export controls in some countries and regions.

Cryptographic technology used

Openloop uses the following cryptographic technology:

About export controls

Export from Japan:

• Cryptographic products are subject to the Foreign Exchange and Foreign Trade Act
• As a consumer product, an export licence is likely not required
• Bulk exports or shipments to particular countries need to be checked individually

United States (EAR):

• Cryptographic products fall under the Export Administration Regulations (EAR)
• Consumer cryptographic products are classified as EAR99 or 5A992.c
• Export to embargoed countries (North Korea, Iran, Syria, Cuba, and others) is prohibited

EU regulation:

• Subject to the Dual-Use Regulation (EU 2021/821)
• Consumer products are normally out of scope

Prohibited uses

Using Openloop for the following purposes is prohibited:

• ✗ Money laundering
• ✗ Terrorist financing
• ✗ Evading economic sanctions
• ✗ Illegal transfers of funds
• ✗ Concealing assets to evade tax
• ✗ Any other illegal activity

Your responsibilities

You are responsible for complying with the following:

1. The laws of your country of residence
   • Laws governing holding and trading crypto assets
   • Tax law (capital gains tax, income tax, and so on)
   • Reporting obligations (for example, reporting transactions above a threshold)
2. Import and export controls
   • Checking the rules before taking this product to another country
   • Not bringing it into embargoed countries
3. Cooperation with KYC
   • Meeting KYC/AML requirements when using exchanges
   • Keeping transaction records as required
4. Tax filing
   • Keeping proper records of crypto-asset transactions
   • Filing accurately with the tax authorities

Disclaimer

▲ Important: your responsibility

The manufacturer and developers make no warranty whatsoever that Openloop meets the export-control conditions of any given country. If you import or export this product, you must check the applicable laws and regulations yourself and obtain any necessary permits.

• The manufacturer and developers are not liable if you break the law
• Laws and regulations can change in any country
• Deciding whether import or export is permitted is your responsibility
• If anything is unclear, consult a legal professional

ℹ Tip: tax treatment of crypto assets is complex. If you are making large transactions, we recommend consulting a tax accountant.

2. Unboxing and Initial Setup

2.1 What’s in the box

When you open the box, check that you have:

• The Openloop device

▲ Note: a USB-C cable is not included. You will need to supply your own USB-C cable (USB 2.0 or later) for charging and firmware updates.

2.2 First Boot

1. Charge: connect to power with a USB-C cable (a PC or a USB charger)
2. Power on: the device starts automatically
3. Splash screen: the Openloop logo appears
4. Choose a language: the “Select Language / 言語を選択” dialog appears. Tap “English” or “日本語” (you can change this later under Settings → Language)
5. Accept the terms: on first boot the end-user licence agreement (EULA) is displayed. Read it and tap “Agree.” Tapping “View full text” shows a QR code so you can read the full agreement on your smartphone
6. Setup begins: after you accept the terms, the setup dialog appears automatically

The licence agreement screen shown on first boot

2.3 Creating or Restoring a Wallet (most important)

On first boot, if no wallet exists, the setup dialog appears automatically.

▲ On firmware v1.1.0 and earlier: this dialog may be replaced by a screen that says “Wallet Corrupted”. Nothing is wrong with your device. Go ahead and choose “Generate” or “Restore” (see 13.2). This false alarm is fixed in v1.1.1 — updating to v1.1.1 or later stops it appearing (see chapter 12).

The automatic dialog on first boot

The “Welcome to Openloop” dialog:

Options:

• “Generate”: create a new wallet (→ go to Step 1)
• “Restore”: restore a wallet from an existing recovery phrase (→ see section 8.4)
• “Cancel”: set up later

ℹ Tip: this dialog also appears automatically after you erase a wallet. You can open the same screen from the “Wallet” screen → “Create Wallet” button.

Creating a new wallet

Step 1: Choose the mnemonic length

Tapping “Generate” brings up the mnemonic length selection screen.

The “Select mnemonic length” dialog:

Which should you choose?

Step 2: Record the recovery phrase

▲ This is the single most important step. Concentrate and do it accurately.

Once you choose 12 or 24 words, a new recovery phrase is generated, and you can view it on the “Wallet” → “Recovery Phrase” screen.

1. Write down the words shown on screen
   • Use the included record sheet
   • The order matters (1st, 2nd, and so on)
   • Watch for spelling mistakes (for example, “work” and “word” are different words)
2. Store it somewhere safe
   • A fireproof safe, a safe deposit box, and so on
   • Keep multiple copies in different places (recommended)

Example recovery phrase (12 words):

1. modify    5. normal     9. mixture
2. rack      6. whisper   10. replace
3. conduct   7. false     11. panda
4. divert    8. solid     12. farm

▲ Warning: this is a sample. Never use it for a real wallet.

Step 3: Wallet creation complete

• Tap the “Done” button
• The message “Wallet created!” appears
• You can see the generated Bitcoin address
• Your wallet is now ready

Checkpoints:

• I wrote the recovery phrase down on paper
• I checked the spelling and the order
• I stored it somewhere safe
• I told my family where it is (optional)

Operations on the “Wallet” screen

On the Wallet screen, buttons are enabled or disabled according to the current wallet state:

What the button colours mean:

• Blue: a normal operation
• Yellow: an operation with a warning (showing secret information)
• Red: a dangerous operation (deleting data)
• Grey: disabled

ℹ Tip: after you erase a wallet, the “Welcome to Openloop” dialog appears again the next time you access it.

2.4 Setting a PIN

After creating a wallet, set a PIN to protect the device.

Step 1: Go to the PIN screen

1. Tap “Security” in the navigation bar → “Set PIN (4-6 digits)”

Step 2: Enter the PIN

1. Enter a new PIN (4–6 digits)
   • Recommended: 6 digits or more
   • Avoid: 1234, 0000, your birthday, or anything else easy to guess
2. Enter it again to confirm
   • Type the same PIN
3. Done
   • The message “PIN set” appears

ℹ Tip: write your PIN down so you do not forget it (and store it somewhere separate from your recovery phrase).

▲ PIN entry limits (lockout)

For security, entering the PIN incorrectly several times in a row temporarily locks the device:

▲ Most important: getting it wrong 10 times in a row makes the device automatically perform a factory reset. In addition to your wallet (recovery phrase), PIN, and all settings, your FIDO2 passkeys and PIV keys and certificates are also completely erased and can never be recovered.

Crypto assets can be restored from your recovery phrase, but passkeys must be registered again at each service, and PIV keys must be regenerated with new certificates issued (see also 8.1, 9.4, and 10.7).

After nine failures, wait for the lockout to clear and then enter the correct PIN calmly. Powering the device off does not cancel the pending erase — the confirmation screen reappears on the next boot.

2.5 Language

You can choose Japanese or English.

1. Tap “Settings” → “Language”
2. Choose “日本語” or “English”
3. The whole interface switches to the language you chose

ℹ Tip: you can change the language at any time.

2.6 Sound

You can configure the click sound and other tones.

Turning the click sound on and off

1. “Settings” → “Sound” → “Click sound”
2. Use the toggle to turn it on or off

ℹ Tip: you can turn the click sound off when using the device somewhere quiet.

Adjusting the volume

1. “Settings” → “Sound” → “Volume”
2. Adjust with the slider
   • 0% (silent) to 100% (maximum)

ℹ Tip: the confirmation tone played when signing a transaction also follows the volume setting.

3. Reading the Screen and Basic Operation

3.1 Screen layout

The Openloop screen consists of three areas:

┌────────────────────────────────────────────────────┐
│                   [ Status bar ]                   │  ←  Battery / BLE / USB
├────────────────────────────────────────────────────┤
│                                                    │
│                 [ Content area ]                   │  ←  Main information and buttons
│                                                    │
├────────────────────────────────────────────────────┤
│ Home Send Receive Wallet Passkey Security Coin Set │  ←  Navigation bar (scrolls sideways)
└────────────────────────────────────────────────────┘

Status bar (top)

• Left: menu icon, application title
• Right: battery level, BLE connection status, USB connection status

Navigation bar (bottom)

The navigation bar scrolls horizontally and gives direct access to eight screens:

ℹ Tip: swipe the navigation bar left and right to reach the items that are hidden.

3.2 Touch basics

• Tap: press the screen lightly with a finger (to select a button)
• Swipe left/right: swiping the content area sideways switches to the adjacent screen, so you can move intuitively between the eight screens in the navigation bar
• Swipe right (back): while an overlay such as a QR code display or the camera is showing, swiping right returns to the previous screen
• Swipe up/down: scrolls long content
• Long press: not used at present

ℹ Tip: tapping a button plays a click sound (which you can turn on or off in Settings).

Working with dialogs

In confirmation dialogs and signing approval screens, buttons are laid out like this:

• Right side: the affirmative button (OK, Agree, Sign, and so on)
• Left side: the negative button (Cancel, Reject, and so on)

3.3 Home screen

Shows the current state of your wallet at a glance.

What it shows:

• The Openloop logo
• Wallet type: the current connection mode (Air Gap / Air Gap / USB / Air Gap / BLE / Air Gap / USB / BLE)
• Mainnet addresses for five currencies (scroll up and down):
  • BTC: Bitcoin mainnet address
  • ETH: Ethereum mainnet address
  • XRP: XRP mainnet address
  • SOL: Solana mainnet address
  • TRX: TRON mainnet address

ℹ Tip: the home screen always shows mainnet addresses. To check a testnet address, switch networks on the “Receive” screen.

Default coin

Scrolling the address card on the home screen (headed “Default coin”) up and down highlights the selected currency in the accent colour. That is the “default coin,” and it becomes the app mode reported to wallet software on your PC over USB. This is equivalent to Ledger’s “app switching.”

Normally it switches automatically in response to requests from the wallet software, but some wallet software requires you to select it manually.

3.4 Receive screen

Shows the address and QR code for receiving crypto assets.

Openloop is a hierarchical deterministic (HD) wallet: following BIP32/BIP44, it derives many keys hierarchically from a single master seed. Any derived key can be used, and changing the key for each transaction helps protect your privacy.

The Receive screen can show representative addresses for Bitcoin, Ethereum, XRP, Solana, and TRON, as well as any public-key address your wallet holds by specifying a BIP44 custom path.

How to use it:

1. Tap “Receive” in the navigation bar
2. Choose a currency (Bitcoin / Ethereum / XRP / Solana / TRON / custom path)
3. The receiving address appears
4. Tap “Show QR” to display the QR code

What each currency choice does:

If you choose a custom path (BIP32/BIP44):

1. Select “Custom path (secp256k1)” or “Custom path (Ed25519)”
2. Choose the “Coin” (BTC / ETH / XRP / SOL / TRX)
3. Choose the “Account” (0–9)
4. Choose the “Change” value ((none) / 0 (Ext) / 1 (Int); the default is 0 (Ext))
5. Choose the “Index” ((none) / 0–99)
6. The “Full path” field at the bottom shows the derivation path (for example m/84'/0'/0'/0/0), with the corresponding address below it

This lets you display and verify on Openloop any address your companion wallet is using.

ℹ Tip: choosing “(none)” for Change or Index omits that level, making the path shallower. Use this when you need a three-level path, as Solana does.

BIP32 derivation path format:

m / purpose' / coin_type' / account' / change / index

Standard paths by currency:

▲ Note: for XRP the derivation path changes with the curve you select (Ed25519 hardens every level). Set the curve on the “Connect Wallet” screen (see 4.1).

ℹ Example: if you want to use several receiving addresses for different purposes (work and personal, say), use addresses with different indexes.

For details, see “5. Receiving Crypto Assets”

ℹ Tip: scanning the QR code with a phone app avoids address typos.

3.5 Send screen

Signs transactions so you can send crypto assets.

▲ Important: this screen is for signing transactions using the Air Gap method (QR codes).

Air Gap (QR code):

• Tap the “Scan transaction QR” button
• Scan the transaction QR code shown by your companion wallet (Sparrow Wallet, for example)
• The signing confirmation screen appears
• For details see “6. Sending Crypto Assets”

USB / BLE:

• You do not need to press anything on this screen
• When your companion wallet (MetaMask, for example) sends a signing request, the confirmation screen appears automatically
• You must set up the companion wallet connection in advance (see “4. Pairing with a Companion Wallet”)

▲ Important: Openloop only signs. The actual send (broadcast) is performed by your companion wallet.

3.6 Other screens

An overview of the screens you can reach directly from the navigation bar. See the relevant chapter for details.

ℹ Tip: the wallet pairing feature is reached from “Connect Wallet” on the “Wallet” screen. See “4.1 The Connect Wallet screen” for details.

4. Pairing with a Companion Wallet

▲ Important: before you use Openloop, always set up the connection with your wallet software (your companion wallet).

Openloop is a signing-only device. To actually send and receive crypto assets, you need to pair it with wallet software (a companion wallet).

How wallet pairing works

Choosing a connection method

ℹ About security: with every method, the private key never leaves the Openloop device, and by design you must always approve the signature on the device itself.

4.1 The Connect Wallet Screen

How to get there: “Wallet” in the navigation bar → “Connect Wallet”

This screen displays the public-key information needed to pair with a companion wallet, as a QR code.

When you need it

ℹ Tip: for USB and BLE, as long as the transport is enabled on Openloop, you can pair without going through this public-key QR screen. In MetaMask and similar wallets, choose “Connect hardware wallet.”

Choosing a currency

Select the currency to pair from the dropdown menu:

• Bitcoin: pair with Sparrow Wallet and others over Air Gap
• Ethereum: pair with a companion wallet over Air Gap
• XRP (Ripple): pair over Air Gap, or change the curve setting
• Solana: pair with a companion wallet over Air Gap

Options by currency

Bitcoin

Script choices:

▲ Important: the script type you choose here must match the wallet type you create in your companion wallet. If they do not match, the addresses will differ.

Tapping “Show QR” displays the extended public key for the selected script (zpub / ypub / xpub / Zpub) as a QR code.

Ethereum

There are no options. Tapping “Show QR” displays the address information as a QR code.

XRP (Ripple)

▲ An important note about the XRP curve setting

The XRP curve setting affects all three transports — Air Gap, USB, and BLE. This is different from the other currencies.

Background:

XRP Toolkit (via the hw-app-xrp library) has a bug: it always sends P2=0x40 (secp256k1), even when you are using an Ed25519 address.

Recommended settings:

• Using XRP Toolkit: set it to “Ed25519”
• Other wallets: “Auto” works fine

ℹ Tip: Ed25519 is the newer format and the default for software wallets. Unless you have a specific reason not to, we recommend “Ed25519.”

Solana

“BIP32 Path” lets you choose how deep the derivation path goes.

▲ Important: a different depth derives a different address. Match it to the path format your companion wallet uses. If they do not match, the addresses will differ. If you are unsure, leave it at the default of 3 levels.

Tapping “Show QR” displays the Solana public-key information for the selected depth as a QR code.

Pairing at a glance

1. Air Gap pairing (Bitcoin + Sparrow Wallet)
   1. In Sparrow Wallet, choose “New Wallet” → “Airgapped Hardware Wallet”
   2. Display the QR code on Openloop (“Wallet” → “Connect Wallet” → “Bitcoin”)
   3. Scan the QR in Sparrow → paired
2. USB pairing (Ethereum + MetaMask)
   1. In MetaMask, choose “Add account” → “Hardware wallet” → “Ledger”
   2. Connect Openloop over USB
   3. Select an address → paired
3. BLE pairing (Ethereum + MetaMask Mobile)
   1. Pair over BLE on Openloop first (see “7.4 BLE (Bluetooth) in detail”)
   2. In MetaMask Mobile, choose “Hardware wallet” → “Bluetooth”
   3. Select Openloop → paired

▲ Note: for step-by-step instructions on each method, see “6. Sending Crypto Assets.”

▲ A caution when using several wallets

Do not run several wallet applications at the same time.

• ✗ Running Sparrow Wallet and MetaMask simultaneously
• ✗ Opening different wallets in several browsers

What goes wrong:

• Contention for the USB port
• Confusion between signing requests
• Unexpected errors

The right way:

• ✓ Sending Bitcoin: run only Sparrow Wallet
• ✓ Sending Ethereum: run only MetaMask
• ✓ When you are done, quit the wallet software before working with another currency

5. Receiving Crypto Assets

▲ Important: Openloop has no balance display. To check whether funds have arrived, use your companion wallet (Sparrow Wallet, MetaMask, and so on) or a blockchain explorer.

5.1 How receiving works

To receive crypto assets, you need to give the sender your receiving address.

There are two ways to obtain a receiving address:

ℹ Security tip: checking that the address shown in your companion wallet matches the one on Openloop lets you detect address tampering by malware.

The basic flow:

1. Confirm the currency and network
2. Obtain the receiving address (from the companion wallet or from Openloop)
3. Have the funds sent from an exchange or another wallet
4. Confirm the transaction (on the blockchain)

5.2 Checking which crypto assets are supported

Openloop supports several crypto assets and networks. Check that the currency you want to receive is supported.

ℹ Note: you do not have to do this before every transaction. As long as the correct currency and network are configured in your companion wallet, they are determined automatically at signing time.

Getting to the Coin & Network screen

Tap “Coin” in the navigation bar

Supported currencies

ℹ Broad Ethereum support:

Openloop supports every EVM-compatible network and every ERC-20 token.

Built-in data:

• 2,599 major tokens and 215 networks are built in
• Token names and network names are shown on the signing confirmation screen

When something is not built in:

• Tokens that are not built in: instead of a token name, the screen shows “ERC-20 Token” or “Unknown ERC-20,” together with an orange warning, “Unknown token - verify contract!” The contract address is shown in full
• Networks that are not built in: instead of a network name, the screen shows something like “Chain ID 12345,” and the currency symbol for the amount and fee becomes “ETH?”
• Signing is still possible in both cases

For details, see “14. Supported Crypto Assets and Networks.”

Mainnet vs. testnet

▲ Important: choosing the wrong network can cost you your assets.

ℹ If you are new to this: we strongly recommend practising on testnet first, then moving to mainnet.

Networks per currency:

Additional Ethereum networks (layer 2 and so on):

• Arbitrum One / Arbitrum Sepolia
• Optimism / Optimism Sepolia
• Base / Base Sepolia
• And many more

▲ Warning: always confirm that the sending and receiving networks are correct.

5.3 Displaying a receiving address on Openloop

Use the “Receive” screen on Openloop when you want an address without using a companion wallet, or when you want to verify that the address shown in your companion wallet is correct.

Step 1: Go to the Receive screen

1. Tap “Receive” in the navigation bar
2. The receiving address for the current currency and network appears

ℹ Address verification tip: when you pick a currency on the Openloop Receive screen, the address for “Account 0, Index 0” is shown by default.

Using a custom derivation path (BIP32/BIP44)

If your companion wallet uses a different account or index, you can specify a custom BIP32/BIP44 path on Openloop to display the same address.

How to do it:

1. On the Receive screen, choose “Custom path (secp256k1)” or “Custom path (Ed25519)” from the currency dropdown
2. Select “Coin,” “Account,” “Change,” and “Index” (see 3.4)
3. The “Full path” field shows the derivation path, with the corresponding address below it

Example 1: Sparrow Wallet is using the second address

• Sparrow: the address at Account 0, Index 1
• Openloop: specify Account=0, Index=1, Coin=BTC on the custom path → the same address appears

Example 2: MetaMask with several accounts

• MetaMask: the address of “Account 2” (MetaMask’s second account)
• Openloop: specify Account=1, Index=0, Coin=ETH on the custom path → the same address appears

ℹ Note: MetaMask’s “Account 1” corresponds to Openloop’s Account=0 (because counting starts at zero).

Example addresses:

• Bitcoin: bc1q... or tb1q... (testnet)
• Ethereum: 0x...

Step 2: Show the QR code

1. Tap the “Show QR” button
2. The QR code fills the screen
3. Scan it with a phone or similar to read the address

ℹ Tip: tapping the QR code returns to the address display.

Step 3: Ways to copy the address

Option 1: Type it manually

• Type the displayed address exactly (not recommended — risk of typos)

Option 2: Scan the QR code

• Scan the QR code with a wallet app on your phone (recommended)

Option 3: USB / BLE

• Retrieve it automatically from the companion wallet (easiest)

5.4 Having funds sent from an exchange or another wallet

Example: sending from an exchange (Bitcoin)

1. Sign in to the exchange
2. Go to the withdrawal screen
   • Choose the “Withdraw” or “Send” menu
3. Choose the currency: Bitcoin (BTC)
4. Enter the receiving address
   • Scan the QR code on Openloop’s Receive screen, or copy the address
5. Enter the amount
   • How much BTC you want to send
6. Check the network fee
   • The exchange calculates it automatically
7. Confirm and send
   • Complete any security checks such as two-factor authentication
8. Wait for the transaction to confirm
   • Minutes to hours (for Bitcoin)

▲ Warning: test with a small amount the first time. Confirm the address is correct before sending a real amount.

ℹ Tip: if you want to practise on testnet, you can obtain coins from a testnet faucet.

5.5 Confirming a deposit

Openloop itself has only limited balance display. You can check in these ways:

Option 1: A blockchain explorer

• Bitcoin: blockstream.info
• Ethereum: etherscan.io
• XRP: xrpscan.com

Search for your address to see the transaction history and balance.

Option 2: Your companion wallet

• Check the balance in Sparrow Wallet, MetaMask, and so on

5.6 Receiving ERC-20 tokens

ERC-20 tokens are tokens that run on the Ethereum blockchain (USDT, USDC, DAI, JPYC, and so on).

The key point

The receiving address for ERC-20 tokens is the same as your ETH address

▲ Important: you use your ordinary Ethereum address (0x...) to receive ERC-20 tokens too. You do not need a separate address per token.

About the differences between networks (chains)

▲ Important: ERC-20 tokens differ by network (chain). The same token name on a different network is a different thing.

EVM networks supported by Openloop (215 networks: 129 mainnets + 86 testnets)

Major networks (excerpt):

See the product specification for the complete network list.

Characteristics of the major networks:

1. Ethereum Mainnet:
   • The most common; almost every exchange supports it
   • Fees (gas) are high (sometimes $5–$50 or more)
   • The highest security
2. Base (Coinbase L2): ★ newly supported
   • A layer 2 operated by Coinbase
   • Very cheap fees (under $0.01)
   • Easy to use alongside Coinbase
3. Arbitrum One / Optimism:
   • Ethereum layer-2 solutions
   • Extremely cheap fees ($0.01–$1)
   • Fast processing (seconds)

How to receive

1. Choose the network:
   • Withdrawing from an exchange → choose a network the exchange supports
   • Receiving from a personal wallet → choose the same network as the sender
2. Check the address: confirm your Ethereum address (0x...) on the “Receive” screen
3. Request the transfer: have the exchange or wallet send ERC-20 tokens to that address

▲ Important: the address may be the same, but if the network differs the funds will not arrive. Sender and receiver must always choose the same network.

Frequently asked questions

Q: Do I need a dedicated address for USDT? A: No. A single Ethereum address receives ETH and every ERC-20 token (USDT, USDC, DAI, and so on).

Q: My exchange asks me to choose a “network.” What should I pick? A: Choose as follows:

• Choose ERC-20 or Ethereum (correct)
• ✗ Do not choose TRC-20 (the Tron network) or BEP-20 (BSC)
• ✗ Choosing the wrong network loses your assets

Q: How do I check whether the tokens arrived? A: Search for your address on Etherscan (https://etherscan.io/) to see your ETH and ERC-20 balances.

Examples of supported ERC-20 tokens

Openloop supports the major ERC-20 tokens:

ℹ Tip: because ERC-20 tokens run on the Ethereum network, transfer fees (gas) are paid in ETH.

6. Sending Crypto Assets

6.1 The basics of sending

Openloop is a signing-only device. The actual sending process works like this:

ℹ What “Air Gap” means: exchanging data purely through QR codes, without USB or BLE. Choose it when you do not want any electronic communication between devices.

6.2 Preparing your wallet software

The main wallet applications that work with Openloop:

ℹ About compatibility: Openloop uses the Ledger-compatible protocol over USB and BLE, and the KeyStone-compatible protocol over QR codes. Ledger-compatible applications other than Ledger Live, and KeyStone-compatible applications, generally work.

Installing MetaMask Mobile (for Ethereum, recommended):

1. Install “MetaMask” from the App Store (iOS) or Google Play (Android)
2. Create (or import) a wallet
3. Set up BLE pairing with Openloop (see 6.5)

Installing Sparrow Wallet (for Bitcoin):

1. Official site: sparrowwallet.com
2. Download the version for your OS
3. After installing, pair it with Openloop (see Appendix 15.5)

6.3 Air Gap (scanning QR codes)

This method exchanges everything through QR codes, without USB or BLE. It suits anyone who wants to operate without electronic communication between devices. For everyday use we recommend USB or BLE (sections 6.4 and 6.5).

Supported wallets (KeyStone-compatible)

• Sparrow Wallet (Bitcoin) — verified
• MetaMask Mobile (Ethereum) — verified
• AirGap Vault (multi-chain) — verified
• Many other KeyStone-compatible wallets

The basic Air Gap flow

1. Export the public key: Openloop → QR code → companion wallet
2. Build an unsigned transaction: companion wallet → QR code
3. Sign: scan on Openloop → review the details → sign
4. Return the signed data: Openloop → QR code → companion wallet
5. Broadcast: the companion wallet sends it to the network

ℹ What BBQr is: a format that splits large data across several QR codes. Openloop scans all the frames automatically.

ℹ Detailed tutorial: for step-by-step Air Gap instructions, see “15.5 Tutorial: Sparrow Wallet (Bitcoin Air Gap).”

Advantages and disadvantages of Air Gap

Advantages:

• The highest security (no internet connection)
• Zero risk of malware infection
• Privacy protection (no IP address leakage)

Disadvantages:

• Slightly more complex to operate
• Requires QR code scanning (a camera is essential)

6.4 USB

With USB you connect your PC and Openloop directly and sign. It works with HID-capable wallet software.

Choosing a USB mode

ℹ Recommended: choose Compatible mode to use anything other than an Openloop-aware companion wallet.

Supported wallets (compatible mode)

• MetaMask (Ethereum / ERC-20) — verified
• Rabby (Ethereum / ERC-20) — verified
• XRP Toolkit (XRP) — verified
• Many other WebHID-capable wallets

Tip: MetaMask supports Ethereum and ERC-20 tokens. To send Bitcoin, use the QR-code method (Sparrow Wallet).

Sending (example: MetaMask × Ethereum)

Step 1: Turn USB on in compatible mode

1. On Openloop
   • “Settings” → “USB”
   • Switch it to “ON”
   • Choose “Compatible” mode (when pairing with an existing wallet such as MetaMask)

Step 2: Connect your PC and Openloop

1. Connect with a USB-C cable
2. Open MetaMask (the browser extension)
3. Choose “Connect hardware wallet”

Step 3: Connect the device in MetaMask

1. Choose “Ledger”
2. WebHID detects Openloop
3. It appears in the list as “Openloop” or “Ledger Nano S”
4. Click to connect
5. The account selection screen appears

Step 4: Send

1. Click “Send”
2. Enter the destination address
3. Enter the amount
4. Check the gas fee
5. “Next” → “Confirm”

Step 5: Review and sign on Openloop

1. The confirmation screen appears on Openloop
   • Destination (the recipient’s address)
   • Amount (how much ETH is being sent)
   • Gas fee
   • Network (chain ID)
2. Choose “Sign” (right) rather than “Reject” (left)
3. If the device was locked, you will be asked for your PIN (when you are asked depends on the “PIN lock timing:” setting on the Security screen. Setting it to “On sleep” requires a PIN for every signature, which is the most secure)
4. Signing complete

ℹ For details of the confirmation screen, see “6.7 The signing confirmation screen in detail.”

Step 6: Broadcast

• MetaMask sends the transaction automatically
• The transfer appears in your history as “Confirmed”

Done: the transaction has been sent to the Ethereum network from MetaMask.

Advantages and disadvantages of USB

Advantages:

• Simple to operate (no QR codes)
• Fast (quick data transfer)
• Access to MetaMask’s rich DeFi and NFT features

Disadvantages:

• Requires a USB connection (you need a cable)
• Slightly less secure than Air Gap
• Exposed to malware risk on the PC side

6.5 BLE (Bluetooth)

Connect to a phone or tablet over Bluetooth.

Openloop implements the Ledger-compatible BLE protocol, so it works wirelessly with compatible apps.

Supported wallets (compatible mode)

• MetaMask Mobile (iOS / Android) — verified
• Many other Ledger-compatible mobile apps

Note: Ledger Live Mobile is not supported because it checks for genuine Ledger devices.

▲ Pairing in advance is mandatory

Important: to use BLE, you must complete pairing beforehand. Without pairing, BLE will not connect.

Recommended: pair while registering the device in Openloop Connect

The clearest way to pair is to register the device in Openloop Connect (mobile). The registration flow completes your phone’s BLE pairing at the same time.

1. Install Openloop Connect (mobile) (see the Connect manual)
2. Turn BLE on in Openloop’s settings
3. Tap “Add device” in Openloop Connect
4. The BLE scan finds nearby Openloop devices → tap “Connect”
5. Tap “Pair” in your phone’s BLE pairing dialog
6. Registration complete

From then on, when you connect to Openloop from another app such as MetaMask Mobile, pairing is already done at the OS level — just choose “Connect hardware wallet” in that app.

Pairing directly from MetaMask Mobile and similar apps

You can also pair directly from a companion wallet such as MetaMask Mobile, without using Openloop Connect (mobile).

Step 1: Turn BLE on

1. On Openloop
   • “Settings” → “BLE”
   • Switch it to “ON”

Step 2: Start pairing

1. Scroll down the “Settings” screen and tap the “Start pairing” button below the BLE toggle
2. Openloop shows “Waiting…” and enters pairing mode
3. There is a 30-second timeout

Step 3: Pair from your phone

1. Launch MetaMask Mobile or another compatible app
2. “Settings” → “Security” → “Hardware wallet”
3. Search for “Openloop-XXXX” (XXXX is four alphanumeric characters unique to the device)
   • If you have several Openloop devices, these four characters tell them apart
   • Some apps simply show “Openloop”
4. Pairing request
   • A six-digit code appears on your phone
5. The same code appears on Openloop
   • Check that the codes match
   • The device asks, “Is this number shown on the other device?”
6. Tap “Approve” on Openloop
   • If the codes do not match, tap “Reject”

Step 4: Pairing complete

• A tone plays
• Your phone and Openloop are connected
• They connect automatically from now on

Sending (example: MetaMask Mobile × Ethereum)

Once pairing is done, here is how to send Ethereum using MetaMask Mobile.

Step 1: Add the account in MetaMask Mobile

1. Launch MetaMask Mobile
2. Tap the account name at the top of the wallet screen
3. “Add account” → “Connect hardware wallet”
4. Choose “Ledger”
5. The connected Openloop appears
6. Select the account (address) to import
7. Tap “Unlock”

Step 2: Start the transfer

1. Select the imported account in MetaMask Mobile
2. Tap “Send”
3. Enter the destination address (or use “Scan QR code”)
4. Enter the amount
5. Check the gas fee
6. Tap “Confirm”

Step 3: Confirm the signature on Openloop

When MetaMask Mobile sends the signing request, the confirmation screen appears on Openloop. If the device is locked, you will be asked for your PIN.

ℹ For details of the confirmation screen, see “6.7 The signing confirmation screen in detail.”

Step 4: Sign

1. Review the details
2. Tap “Sign”
3. Signing completes inside the secure element

Step 5: Send the transaction

• Once signing finishes, the result is returned to MetaMask Mobile
• MetaMask Mobile broadcasts the transaction automatically
• The transfer appears in your history as “Confirmed”

Done: the transaction has been sent to the Ethereum network.

ℹ Tip: opening the transaction details from your history gives you a link to a block explorer.

Removing pairing data

To unpair:

1. Go to the “Settings” screen
2. Tap the “Unpair” button
3. Tap “OK” on the confirmation screen

▲ Note: after unpairing you will need to pair again.

Advantages and disadvantages of BLE

Advantages:

• No cable (wireless)
• Works with phones and tablets
• Usable while you are out

Disadvantages:

• Requires pairing
• Depends on radio conditions
• Less secure than Air Gap

6.6 Sending ERC-20 tokens

Sending ERC-20 tokens (USDT, USDC, DAI, and so on) works essentially the same way as sending ETH, but there are a few important differences.

Essential background

▲ Gas fees must be paid in ETH

When you send an ERC-20 token, the fee is paid in ETH. So:

• Before sending, make sure your Ethereum address holds enough ETH
• Holding only USDT is not enough — without ETH you cannot send
• ℹ Rule of thumb: keep $5–$50 worth of ETH on hand (on mainnet)

How to send (essentially the same as ETH)

You can send ERC-20 tokens using the same three methods as ETH:

1. Air Gap (QR code)

• Wallets: Sparrow Wallet (partial support for USDT and others), BlueWallet
• Steps: the same as 6.3 (sending in PSBT form)

2. USB (compatible mode)

• Wallets: MetaMask (via WebHID)
• Steps: the same as 6.4 (turn on USB compatible mode)

3. BLE (Bluetooth)

• Wallets: MetaMask Mobile (iOS / Android)
• Steps: the same as 6.5

What Openloop shows you

ℹ For details of the confirmation screen, see “6.7 The signing confirmation screen in detail.”

Frequently asked questions

Q: Why do I need ETH to send an ERC-20 token? A: Because the fee (gas) paid to the miners (validators) who process transactions on the Ethereum network is denominated in ETH.

Q: How much gas do I need? A: It depends on network congestion:

• Ethereum Mainnet: $5–$50 (over $100 when congested)
• Arbitrum One: $0.01–$1 (very cheap)

Q: I tried to send USDT and got an “insufficient gas” error A: Your ETH balance is too low. Send a small amount of ETH ($10–$50) from an exchange.

Q: My exchange withdrawal screen asks me to “select a network” A: Choose the same network you selected on Openloop:

• Openloop on “Ethereum Mainnet” → choose “ERC-20” or “Ethereum” at the exchange
• Openloop on “Arbitrum One” → choose “Arbitrum” at the exchange

Q: Do you support TRC-20 or BEP-20 USDT? A: For sending tokens such as USDT with Openloop, only ERC-20 (Ethereum-family networks) is supported. TRC-20 tokens are not supported, although sending TRON’s native currency (TRX) is. BEP-20 is an ERC-20-compatible token on BNB Smart Chain and is supported as an EVM-compatible chain.

Troubleshooting

Checklist when a token will not send:

1. Is your ETH balance sufficient? ($10 or more recommended)
2. Is the network correct? (sender and receiver must match)
3. Is the contract address correct? (is it a scam token?)
4. Does your wallet software support ERC-20?

6.7 The signing confirmation screen in detail

When you sign a transaction on Openloop, the items shown on the confirmation screen differ by asset type. This section covers each currency and token in detail.

ℹ Timeout: the confirmation screen shows a countdown (starting at 90 seconds) in the top right. If you do nothing for 90 seconds, the request is automatically rejected and an error is returned to your companion wallet. In that case, start the signature again from the wallet.

ℹ Addresses are shown in full: Openloop never abbreviates destination addresses or hashes. Check the whole value — not just the start and end, but the middle too.

6.7.1 Bitcoin (BTC)

What is shown:

What each item means:

Types of Bitcoin address:

▲ Note: Openloop generates bc1q... (Native SegWit) addresses.

▲ Taproot cannot be signed: if you create a Taproot (m/86') account in your companion wallet, Openloop shows “Cannot sign: Taproot (P2TR) is not supported” on the confirmation screen and disables the “Sign” button. In Sparrow Wallet and similar, choose Native SegWit (P2WPKH), Nested SegWit, or Legacy instead.

Two safety warnings on the confirmation screen:

6.7.2 Ethereum (ETH)

What is shown:

What each item means:

ℹ If the fee exceeds 0.01 ETH, an orange warning appears: “Gas fee is high!”

Why checking the chain ID matters:

▲ Warning: sending to a network with a different chain ID can lose your assets.

ℹ Networks that are not built in: for networks outside the 215 built-in ones, the screen shows something like “Chain ID 12345” instead of a name, and the currency symbol for the amount and fee becomes “ETH?”. Signing is still possible, so check the network information in your companion wallet before you sign.

6.7.3 ERC-20 tokens

What is shown:

What each item means:

Official contract addresses for major tokens (Ethereum Mainnet):

▲ Important: “fake tokens” with different contract addresses exist. Always confirm the official address on the project’s website, CoinGecko, or a similar source.

ℹ Tokens that are not built in: for tokens outside the 2,599 built-in ones, the screen shows “ERC-20 Token” or “Unknown ERC-20” instead of a name, together with an orange warning, “Unknown token - verify contract!” Signing is still possible, so compare the contract address (shown in full) with your companion wallet before you sign.

6.7.4 XRP (Ripple)

What is shown:

What each item means:

Characteristics of XRP addresses:

About destination tags:

When sending XRP to an exchange, a destination tag is often required.

• When a destination tag is required: the exchange’s XRP address is shared among many users, and the tag identifies you
• When it is not required: sending to a personal wallet (an address that is yours alone)

▲ Warning: getting the destination tag wrong when sending to an exchange can cost you your assets.

About the XRP curve setting:

XRP supports two elliptic curves:

▲ Important: when using XRP Toolkit, go to “Wallet” → “Connect Wallet” → select XRP → set “Curve” to Ed25519. Leaving it on “Auto” can make signing fail. See “4.1 The Connect Wallet screen” for details.

6.7.5 Solana (SOL)

What the confirmation screen shows:

Solana supports both transaction signing and off-chain message signing. The display falls into three patterns.

▲ The blind-signing warning: when you see “Unknown program,” Openloop could not interpret the contents of the transaction. The “Sign” button remains enabled, so make absolutely sure you know what you are signing by checking in the dApp. If it looks unfamiliar, choose “Reject.”

6.7.6 TRON (TRX)

What the confirmation screen shows:

TRON transactions are encoded in protobuf format.

▲ The blind-signing warning: the only TRON transaction Openloop can read is a plain TRX transfer. A TRC-20 token transfer (USDT-TRC20 and the like) is a smart-contract call, which the device cannot interpret: destination, amount and fee all become “See dApp” and a two-line orange warning appears — “Unknown contract” and “Verify in dApp.” The “Sign” button remains enabled, so make absolutely sure you know what you are signing by checking in the dApp. If it looks unfamiliar, choose “Reject.”

6.7.7 Other EVM chains

Supported EVM chains:

Openloop supports 215 EVM chains (129 mainnets + 86 testnets):

Points to watch when confirming a signature:

1. Check the native currency
   • Fees (gas) are paid in that chain’s native currency
   • For example: POL on Polygon, BNB on BNB Chain
2. Not the same as bridging
   • Openloop only handles transfers within a single chain
   • Moving between chains (bridging) requires a separate bridge service
3. Address format
   • Every EVM chain uses the same 0x... address format
   • The same private key produces the same address

6.7.8 Signing screens other than transfers

Openloop handles several kinds of signing request beyond simple transfers. The title at the top of the screen tells you which one it is.

▲ “Approve” and “Set Approval For All” deserve special care

If the “Contract Call” screen shows “Method: Approve” together with “Amount: Unlimited,” you are granting that contract the right to withdraw an unlimited amount of your tokens.

“Method: Set Approval For All” with “Allow: All NFTs” likewise grants the right to move every one of your NFTs.

Never sign these except on a DEX or marketplace you trust. This is one of the classic ways assets are drained.

If it shows “Revoke (0)” instead, that is a revocation of permission and is safe.

Openloop also decodes and displays other methods such as delegated transfer, NFT transfer, multi-send, and batch send.

▲ The “Unverified contract” warning (red)

This appears in red for an EIP-7702 authority delegation when the delegate is not on the known list. If it looks unfamiliar, choose “Reject.”

6.7.9 Signing security checklist

Before you sign a transaction, always check the following:

✓ Mandatory checks:

▲ Do not sign when:

• You do not recognize the address
• The amount is not what you intended
• The fee is abnormally high (ten times normal or more)
• You did not expect a token transfer request
• The chain ID is an unexpected network

ℹ Safe transaction habits:

1. Test small: send a small amount to a new address first
2. Use an address book: register frequently used addresses in your wallet software
3. Double-check: for large transfers, confirm with the recipient through another channel
4. Do not rush: take your time even if someone is pressing you

7. Choosing and Configuring the Connection Method

7.1 Comparing the connection methods

Openloop supports three connection methods. Use whichever suits the task.

All three methods have been verified to a practical standard. Choose freely according to your needs.

7.2 Air Gap (QR code) in detail

Advantages

The highest security

• Zero electronic or radio communication
• Physical data isolation (air gap)
• No risk of malware infection
• Privacy protection (no IP address leakage)

No extra hardware

• No cable needed
• No Bluetooth needed
• All you need is a camera and a display

Future-proof

• More and more wallets support QR codes
• Supports the standard formats (BBQr, UR)

Disadvantages

More complex to operate

• You have to scan QR codes
• Multi-frame codes take time

A camera is essential

• Your PC or phone needs a camera

Recommended for

• ★ Anyone who puts security first
• Anyone managing large holdings
• Anyone whose PC has a camera
• Anyone who does not mind a little complexity

How to use it, in summary

1. Prepare wallet software: install Sparrow Wallet
2. Export the public key: Openloop → QR code → Sparrow
3. Build a transaction: Sparrow → PSBT QR code
4. Sign: Openloop → scan → review → sign
5. Broadcast: Openloop → signed QR code → Sparrow → send

7.3 USB in detail

Advantages

Fast and stable

• Quick data transfer
• Few communication errors
• You can use it while charging

Simple to operate

• Just plug in the cable
• No QR code scanning
• Works with MetaMask (for Ethereum)

Versatile

• Can also be used for firmware updates (OTA)

Disadvantages

Requires a physical connection

• You need a USB-C cable
• You must be near the PC

Security risk

• Exposed to malware on the PC
• You are using an internet-connected PC

Recommended for

• Anyone who wants fast operation
• Anyone managing assets from a PC
• Anyone who does not mind a cable
• Anyone who wants to use Ethereum in MetaMask

How to use it, in summary

1. Turn USB on: “Settings” → “USB” → ON
2. Choose a mode: “Native” or “Compatible”
3. Connect the PC: use a USB-C cable
4. Launch your wallet software: MetaMask, for example
5. The device is recognized: it appears as “Ledger Nano S”
6. Send: operate in the software, sign on Openloop

7.4 BLE (Bluetooth) in detail

Advantages

Wireless

• No cable
• Easy to carry
• Works with phones and tablets

Mobile

• Usable while you are out
• Works with MetaMask Mobile and others

Power-efficient

• Bluetooth Low Energy (BLE) means long battery life

Disadvantages

Pairing required

• One-time setup is needed
• Verifying the code takes a moment

Communication can be unstable

• Depends on radio conditions
• Disconnects if you move too far away

Security risk

• Wireless communication carries risk
• Man-in-the-middle attacks are possible (unlikely, but real)

Recommended for

• Anyone who wants to manage assets from a phone
• Anyone who wants to use it while out
• Anyone who prefers wireless
• Anyone whose transfers are mostly small

How to use it, in summary

1. Turn BLE on: “Settings” → “BLE” → ON
2. Start pairing: scroll down the “Settings” screen and tap “Start pairing”
3. Pair from your phone: connect over Bluetooth in MetaMask Mobile or similar
4. Verify the code: compare the six-digit code
5. Send: operate on the phone, sign on Openloop

7.5 Switching between connection methods

Each method can be enabled and disabled independently.

USB settings

1. “Settings” → “USB”
2. Turn it on or off with the toggle
3. Choose a mode (Native / Compatible)

BLE settings

1. “Settings” → “BLE”
2. Turn it on or off with the toggle
3. Applies immediately

ℹ Tip: disabling both USB and BLE gives you a complete air-gapped mode (QR codes only).

7.6 Power management

Openloop is designed to conserve power and maximize battery life.

Battery

• Capacity: 450 mAh lithium polymer (built-in, custom cell)
• Normal use: about 1 hour
• Sleeping: several hours on standby

Automatic sleep and power off

▲ Important: we recommend using the device above 30% battery (it powers off automatically at 15% or below).

Conditions that prevent sleep

The device will not sleep while:

• Connected over USB (communicating with a host): to keep the connection alive
• Connected over BLE: to keep communication with the phone alive
• Scanning a QR code: while reading a multi-frame QR

BLE idle disconnect timer

For security, a BLE connection is dropped automatically after a period with no traffic.

• The timer resets with every message
• After a disconnect you need to reconnect
• This is a security feature that prevents unauthorized access to an idle BLE connection

ℹ Tip: for long sessions, use the device while charging over USB-C.

7.7 Recommended settings by security level

Maximum security (large holdings)

• ✓ Air Gap only
• ✗ USB disabled
• ✗ BLE disabled
• ℹ A fully air-gapped setup

Balanced (PC use)

• ✓ Air Gap + USB
• ✗ BLE disabled
• ℹ Mainly used from a PC

Balanced (smartphone use)

• ✓ Air Gap + BLE
• ✗ USB disabled
• ℹ Mainly used from a phone

Convenience first (small amounts, mobile)

• ✓ Air Gap + USB + BLE
• ℹ Everything enabled

▲ Warning: if you manage large holdings, we strongly recommend Air Gap mode.

8. Security and Backup

8.1 Managing your PIN

What the PIN is for

• Purpose: to prevent unauthorized use of the device
• Length: 4–6 digits (6 recommended)
• Failure limit: all data is erased automatically after 10 consecutive failures (see 2.4)

PIN lock timing

You can choose from four settings for when the PIN is required. Set it with the “PIN lock timing:” dropdown on the “Security” screen.

ℹ Note: in addition to waking from sleep, every setting other than “Off” also requires a PIN:

• At boot (power on): every time
• When displaying the recovery phrase: every time

▲ Warning: with “Off,” anyone can operate the device. If you manage large holdings, we recommend “On sleep” or “On long sleep.”

Changing your PIN

1. “Security” screen → “Change PIN”
2. Enter the old PIN
3. Enter the new PIN
4. Enter it again to confirm
5. Done

If you forget your PIN

▲ Important: if you forget your PIN, you can recover as follows.

1. Have your recovery phrase ready
   • The 12 or 24 words you wrote down when you created the wallet
2. Perform a factory reset
   • “Settings” → “Factory Reset”
   • ▲ All data is erased
3. Restore your wallet
   • Restore from your recovery phrase
   • See “8.4 Restoring a wallet” for details

Automatic erase after 10 failures

▲ Getting the PIN wrong 10 times in a row makes the device automatically perform a factory reset. It does not lock — the data is erased.

What is erased:

• Your wallet (recovery phrase), PIN, and all settings
• FIDO2 passkeys (you must register again at each service)
• PIV keys and certificates (you must regenerate them and reissue certificates)

How to recover:

1. Restore your wallet from your recovery phrase (crypto assets only)
2. Register your passkeys again at each service
3. Regenerate your PIV keys and reissue certificates

▲ Warning: without your recovery phrase, your assets are lost forever. Passkeys and PIV keys cannot be restored from a recovery phrase.

8.2 Backing up your recovery phrase

Why the recovery phrase matters

▲ Most important: those 12 or 24 words are the only way to protect your assets.

With your recovery phrase:

• You can recover even if you lose the device
• You can recover even if the device breaks
• You can migrate to a new device

Without it:

• Losing the device = losing your assets
• A device failure = losing your assets
• Forgetting your PIN = losing your assets

Displaying the recovery phrase

▲ Warning: make sure nobody is nearby before you do this.

1. “Wallet” screen → “Recovery Phrase”
2. Enter your PIN
   • For security verification
3. The recovery phrase appears
   • The 12 or 24 words are shown in order

ℹ Tip: check periodically that your written copy has not faded (once a year is a good rule).

Storing it safely

Recommended methods:

1. Written on paper (the basics)
   • The included record sheet, or durable paper
   • A waterproof, fire-resistant notebook also works
2. Stamped into metal (advanced)
   • Resistant to fire and flood
   • Use a metal backup product such as Cryptosteel or Billfodl
3. Several copies in different places
   • A safe at home
   • A bank safe deposit box
   • A trusted family member’s home (a different location)

Methods to avoid:

• Photographing it with your phone and storing it in the cloud (the cloud can be hacked)
• Saving it on a computer (malware can steal it)
• Email or cloud storage
• Password managers (risky)
• Keeping only one copy in one place (fire and theft risk)

ℹ Tip: making several copies and storing them in different places reduces the risk from disasters.

8.3 Erasing a wallet

▲ Dangerous operation: this completely deletes the wallet from the device.

Before you erase:

• My recovery phrase is backed up
• I have moved all my assets (or I plan to restore)

How to erase

1. “Wallet” screen → “Erase Wallet”
2. Review the first warning
   • “This will delete your recovery phrase. Your PIN and settings will be kept. This cannot be undone!”
   • Tap “Erase”
3. Review the second, final warning
   • “Are you sure? Only the recovery phrase will be deleted. Your PIN and settings will be kept.”
   • Tap “Erase”
4. Done

▲ Warning: this cannot be undone. Without your recovery phrase, you lose your assets.

▲ Important: erasing a wallet does not require your PIN (unlike “Factory Reset”). If someone else can operate your unlocked device, they could perform this operation. We recommend setting “PIN lock timing:” on the “Security” screen to “On sleep.”

When you might need to erase:

• Before giving the device to someone else
• Before creating a new wallet
• To clear out a test wallet

8.4 Restoring a wallet

You can restore an existing wallet from its recovery phrase.

When you need to restore

• ★ You forgot your PIN (after a factory reset)
• You are moving to a new device
• You erased a wallet by mistake
• You reset the device

How to start a restore

Option 1: from the automatic dialog on first boot

• Starting the device with no wallet shows the “Welcome to Openloop” dialog automatically
• Tap “Restore”

Option 2: from the Wallet screen

• “Wallet” screen → tap the “Create Wallet” button
• Tap “Restore” in the “Welcome to Openloop” dialog that appears

How to restore

Step 1: Choose a restore method

Tapping “Restore” brings up the restore method dialog.

The “Restore Wallet” dialog:

Options:

ℹ Recommended: choose Manual. Restoring from a QR code carries a security risk (the code could be photographed by someone else).

Step 2: Enter the recovery phrase

Manual entry:

1. Enter the first word
   • Start typing on the on-screen keyboard
   • Suggestions appear as you type (from the BIP39 word list)
2. Choose the correct word from the suggestions
3. Enter the remaining words the same way
4. Finish entering all the words (12 or 24)

ℹ Tip: if a word does not appear in the suggestion list, it is probably misspelled. The BIP39 list contains exactly 2,048 words.

QR scanning:

1. The camera opens
2. Hold the recovery phrase QR code in view
3. It is read automatically

Step 3: Restore complete

• The message “Wallet restored” appears
• Returning to the home screen shows the restored addresses

How to verify: check that the addresses on the Receive screen match your previous wallet.

Troubleshooting a failed restore

If you see an “Invalid mnemonic” error:

• Cause 1: a spelling mistake
  • Fix: check the words again (against the BIP39 word list)
• Cause 2: the order is wrong
  • Fix: check the order in your notes
• Cause 3: the number of words is wrong
  • Fix: confirm whether it is 12 or 24 words

▲ Important: if it still will not restore after several attempts, your notes may be wrong. Look for another backup.

9. Using It as a Security Key (FIDO2 / Passkeys)

Openloop also works as a FIDO2/CTAP2 security key. It supports passwordless sign-in to web services and two-factor authentication for PC security, over USB or BLE (with the Openloop Connect mobile app).

▲ Certification status: Openloop is not currently a FIDO Certified Authenticator (FIDO2 Certified) with the FIDO Alliance. The CTAP2/WebAuthn implementation follows the specification, but official FIDO Alliance certification and AAGUID registration (the FIDO Metadata Service) are something we may pursue in future.

9.1 What FIDO2 and passkeys are

FIDO2 (Fast IDentity Online 2) is a secure alternative to passwords. Using a private key stored in Openloop, you can sign in securely to web services and applications from both a PC and a smartphone.

Key characteristics:

• No password: resistant to phishing
• Device authentication: you cannot sign in without your Openloop
• Privacy protection: a different key is used for each service
• Multi-device: works on PCs (Windows / macOS / Linux) and smartphones (iOS / Android)

Supported algorithms:

• ES256 (ECDSA P-256)
• EdDSA (Ed25519)

Two connection paths:

▲ A note for iPhone users: on iOS 17 and later you can connect over BLE through Openloop Connect’s Credential Provider Extension. The iOS picker shows “Openloop Connect” — that is iOS fixing the name to the containing app — but the actual communication is over BLE, not USB.

9.2 Registering a passkey

On a PC (USB):

1. Go to a FIDO2-capable service in your web browser
2. In the security settings, choose “Add a security key”
3. Connect Openloop over USB
4. The registration confirmation appears on the Openloop screen
5. Review it and tap the approve button
6. Registration complete

On a smartphone (BLE + Openloop Connect):

1. Install the Openloop Connect mobile app
2. Pair and select your Openloop device over BLE in the app
3. Enable Openloop Connect as a credential provider in your iOS or Android settings
4. Go to a FIDO2-capable service in your browser and choose the create-passkey option
5. Choose “Openloop Connect” in the OS picker
6. The registration confirmation appears on the Openloop screen
7. Tap the approve button → registration complete

9.3 Signing in with a passkey

On a PC (USB):

1. Sign in to a FIDO2-capable service in a browser or app
2. Choose “Use a security key”
3. Connect Openloop over USB
4. The authentication confirmation appears on the Openloop screen
5. Tap the approve button → signed in

On a smartphone (BLE + Openloop Connect):

1. Go to the sign-in page of a FIDO2-capable service and choose passkey authentication
2. Choose “Openloop Connect” in the OS picker
3. Openloop wakes over BLE and shows the authentication confirmation
4. Tap the approve button → signed in

9.3.1 USB and BLE registration compatibility (generally fine; Google is the exception)

With most services, a single registration lets you use the passkey over either USB or BLE. With major services such as Microsoft, GitHub, Monex, JAL, and SBI VC Trade, one registration works on both transports.

However, some services (Google being the prime example) manage transports strictly per credential, so a passkey registered over USB CTAPHID is not visible to Openloop Connect’s BLE flow (and vice versa). Only for such services do you need to register the passkey twice with the same Openloop device — once over USB and once over BLE. Openloop issues a different credential ID per transport even on the same hardware, so the server records two independent credentials.

ℹ In the device’s “Passkey” list, a 🔌 (USB) or 📶 (Bluetooth) icon to the left of each credential tells you which path it was registered through.

9.4 Managing passkeys

You can manage your registered passkeys from the “Passkey” screen in the navigation bar.

The FIDO2/Passkey section:

• ON/OFF: enable or disable the passkey feature
• Registered passkey list: lists your passkeys by service
• Delete individually: use the trash icon next to each passkey
• Reset passkeys: completely deletes and regenerates every passkey and cryptographic key

▲ Warning: running “Reset passkeys” makes every passkey unusable. You will have to register the security key again at each service.

▲ Important: passkeys cannot be restored from a recovery phrase. Your wallet’s crypto assets can be, but passkeys can never be recovered after a reset or a factory reset. Registering again at each service is the only way back.

9.5 Examples of supported services and apps

Here are examples of services and applications where you can use Openloop as a security key.

Services confirmed to work:

ℹ Tip: you can store up to 100 passkeys (resident keys).

▲ Note: not every FIDO2-capable service accepts a physical security key. Some services and apps accept only the biometrics built into a phone (Face ID or a fingerprint) as a passkey and do not support external security keys. Check whether a “security key” option appears when you register.

10. Using It as a PKCS#11 Signer (PIV)

Openloop also works as a PIV (Personal Identity Verification) PKCS#11 signer. You can use it for SSH public key authentication, PDF signing, TLS client authentication, GPG signing, and more.

▲ Note: to use the PIV features you need the Openloop Connect desktop application. The PKCS#11 library communicates with the Openloop device through Openloop Connect.

10.1 PIV at a glance

Four PIV slots:

Supported algorithms:

• P-256 (ECDSA)
• Ed25519
• RSA-2048

10.2 Preparation

1. Install Openloop Connect: download the latest version from https://crypto.haudi.jp/openloop/connect/
2. Connect Openloop over USB
3. Launch Openloop Connect
4. Turn PIV on: switch it on in the PIV section of the “Passkey” screen in the navigation bar

10.3 Generating keys and creating certificates

Use a PKCS#11 tool (such as pkcs11-tool) to generate PIV keys and create certificates.

The PKCS#11 library is bundled with Openloop Connect, in the pkcs11/ folder under the application’s installation path:

The installation path <app> depends on how you installed the app:

The examples below set the full path for the macOS DMG build in a shell variable:

MODULE="/Applications/Openloop Connect.app/Contents/Resources/pkcs11/libopenloop-pkcs11.dylib"

# Generate a P-256 key in slot 9A
pkcs11-tool --module "$MODULE" --slot 0 --keypairgen --key-type EC:prime256v1 --id 9a

# Generate an RSA-2048 key in slot 9C
pkcs11-tool --module "$MODULE" --slot 1 --keypairgen --key-type rsa:2048 --id 9c

ℹ Step-by-step instructions: for details on SSH authentication, TLS client authentication, and using pkcs11-tool, see the Security Key Guide.

10.4 SSH authentication

You can use an Openloop PIV key for SSH public key authentication.

# Retrieve the public key
ssh-keygen -D "$MODULE"

# Connect over SSH (via PKCS#11)
ssh -I "$MODULE" user@hostname

10.5 PDF signing (Adobe Acrobat)

You can sign PDFs in Adobe Acrobat using an Openloop RSA-2048 key.

1. Acrobat preferences → “Signatures” → “Identities & Trusted Certificates” → “More”
2. “PKCS#11 Modules and Tokens” → “Attach Module”
3. Specify the path to the PKCS#11 library
4. Choose “Sign” in a PDF document and use your Openloop digital ID

▲ Note: launch Openloop Connect before using Acrobat.

10.6 GPG signing

You can use an Openloop PIV key for GPG (GNU Privacy Guard) signing. Through gnupg-pkcs11-scd, you can sign Git commits and cryptographically sign files.

ℹ Note: gnupg-pkcs11-scd supports RSA keys only. EC keys (P-256 / Ed25519) cannot be used for GPG signing.

10.7 Managing PIV keys

Manage them in the PIV section of the “Passkey” screen in the navigation bar.

The PIV section:

• ON/OFF: enable or disable the PIV feature (USB connection required)
• PIV PIN: a separate PIN for PIV operations (see below)
• Slot status: shows the key type and whether a certificate is present for each slot
• Reset PIV: completely deletes every PIV key, certificate, and PIN

About the PIV PIN

The PIV PIN authenticates PIV signing over USB. It is a separate PIN from your wallet PIN.

Characteristics of the PIV PIN:

• 6–8 digits
• Locks after 8 failed attempts
• Managed separately from the wallet PIN

What the PIV PIN is for:

Once a PIV PIN is set, an application on your PC (SSH, Acrobat, and so on) can send the PIN over USB and sign without you approving on the Openloop screen (USB PIN authentication).

ℹ Tip: setting a PIV PIN is convenient when you sign frequently, as with SSH authentication or GPG signing. For important signatures such as PDF signing, it is safer to leave the PIV PIN unset and confirm on screen.

Setting the PIV PIN:

Set the PIV PIN from a PKCS#11 tool on your PC. A confirmation dialog appears on the Openloop screen — approve it.

Deleting the PIV PIN:

Tap the trash icon in the PIV section of the Passkey screen.

▲ Warning: running “Reset PIV” deletes every PIV key and certificate. You will have to set up SSH authentication and PDF signing again.

▲ Important: PIV keys cannot be restored from a recovery phrase. After a reset or a factory reset they can never be recovered. You will have to regenerate the keys and reissue the certificates.

11. Screen Map

Here is how the Openloop screens are organized. You can reach the eight screens directly from the navigation bar, and swipe left and right to move between them.

Openloop navigation bar (scrolls horizontally)
│
├── Home ─────────────── Logo, connection mode, addresses for 5 currencies
│
├── Send ─────────────── Scan transaction QR → display signed QR
│
├── Receive ──────────┬── Choose a currency (7 options) → show address
│                     └── Show QR
│
├── Wallet
│   ├── Create Wallet ──── Generate / Restore
│   ├── Connect Wallet ─── BTC/ETH/XRP/SOL
│   ├── Erase Wallet
│   └── Recovery Phrase
│
├── Passkey
│   ├── FIDO2/Passkey ─── ON/OFF, count, passkey list (delete individually)
│   │                     Reset passkeys (deletes HMAC + seed + all entries)
│   │
│   └── PIV/PKCS#11 ───── ON/OFF, PIV PIN management
│                         Slot status (9A/9C/9D/9E: algorithm + certificate)
│                         Reset PIV (all slots + PIN)
│
├── Security
│   ├── PIN lock timing: ─ On sleep / On long sleep / At boot only / Off
│   ├── Set PIN (4-6 digits) / Change PIN
│   └── Delete PIN
│
├── Coin ─────────────── BTC/ETH/XRP/SOL/TRX
│   ├── Bitcoin ──────── Supported networks, Air Gap format (BBQr/UR), USB/BLE format
│   ├── Ethereum ─────── Supported networks, supported tokens, Air Gap format, USB/BLE format
│   ├── XRP ──────────── Supported networks, Air Gap format, USB/BLE format
│   ├── Solana ───────── Supported networks, Air Gap format, USB/BLE format
│   └── TRON ─────────── Supported networks, USB/BLE format
│
└── Settings
    ├── Sound ────────── Click sound ON/OFF, volume
    ├── Language ─────── Japanese / English
    ├── USB ──────────── ON/OFF, mode (Native / Compatible)
    ├── BLE ──────────── ON/OFF, pairing management
    ├── <span class="symbol warn">▲</span> Factory Reset
    └── About ────────── Version, copyright, open-source libraries

Related sections: initial setup → Ch. 2, screen operation → Ch. 3, connection methods → Ch. 7, security → Ch. 8, passkeys → Ch. 9, PIV → Ch. 10

12. Firmware Update (OTA)

12.1 What an OTA update is

Over-the-air (OTA) updates let you update the device firmware to the latest version.

Why update:

• New features
• Bug fixes
• Security patches
• Performance improvements

▲ Important: Openloop has no internet connectivity. Firmware updates are performed over USB or BLE using Openloop Connect (the desktop or mobile app). You can download Openloop Connect from https://crypto.haudi.jp/openloop/connect/

12.2 How updating works

Openloop firmware updates are performed with Openloop Connect.

The mechanism:

1. Openloop Connect downloads the new firmware from the server
2. It sends the firmware data to Openloop over USB or BLE
3. Openloop verifies and installs the firmware

ℹ Note: the device on its own cannot check for or download updates. It must be connected to Openloop Connect.

When an update can be started

▲ Important: a firmware update can only be started while the device is awake and showing nothing on screen. The update is rejected when:

• The device is asleep (screen off)
• A PIN entry screen is showing (waiting for unlock, changing the PIN, confirming a factory reset, and so on)
• A confirmation dialog or message is showing
• The QR scanner, mnemonic entry, or wallet creation/restore is in progress

This applies even if you have set the PIN lock to “Off.” An update cannot be started while the device is asleep.

If the update is rejected, touch the device to wake it, unlock it if a PIN screen appears, close whatever is on screen, and start the update again.

ℹ Why this restriction exists: replacing the firmware is the most far-reaching operation the device can perform. If the update confirmation appeared on top of the lock screen, the update could be approved without the PIN ever being entered. Requiring an awake, idle device means the update is always approved by someone who can actually operate it.

12.3 Updating over USB

How to update

Step 1: Prepare

• Connect the USB-C cable (charging)
• Battery above 30%
• A stable power source
• Launch Openloop Connect
• The device awake and showing nothing (such as the home screen) — an update cannot be started while it is asleep or on a PIN entry screen

Step 2: Start the update

1. Run “Check for updates” in Openloop Connect
2. If a newer version exists, start the update
3. The “Firmware Update” confirmation dialog appears on Openloop

▲ The dialog warns you not to disconnect. If you do nothing for 30 seconds, it is rejected automatically.

Step 3: Download and verification

1. Choose “Approve” (right) rather than “Reject” (left)
2. The screen shows “Preparing…” then “Downloading,” with a progress bar and the percentage and KB updating
3. When the transfer finishes, it switches automatically to “Verifying” and checks the SHA-256 hash and the firmware signature

Step 4: Installation and restart

1. After successful verification, “Update complete” appears
2. ▲ Never unplug the cable
3. After a “Restarting in 5 seconds” countdown, the device restarts automatically

Step 5: Done

• After restarting, the new version is shown
• Check the version under “Settings” → “About”

Update complete: you can confirm the new version under “Settings” → “About”

12.4 Updating over BLE

You can also update over BLE (the steps are almost identical to USB).

How to update

1. Touch the device to wake it (an update cannot be started while it is asleep or on a PIN entry screen — see 12.2, “When an update can be started”)
2. Connect to your phone over BLE
3. Receive the update notification
4. Tap “Approve”
5. Download → verify → install
6. Restart

▲ Note: keep your phone close to the device during a BLE update so the connection does not drop.

ℹ Also: while asleep on battery power the device does not advertise over BLE. If your phone cannot find it, wake the device first.

12.5 Cautions during an update

▲ Do not

• ✗ Disconnect USB or BLE partway through
  • The firmware could be corrupted
• ✗ Press the power button
  • The update will be interrupted
• ✗ Update on a low battery
  • The device could lose power partway through

Do

• Use a stable power source (USB is recommended)
• Keep the battery above 30%
• Wait until the update finishes (2–3 minutes)
• Do not move the device

12.6 If an update fails

If an update fails, one of the following error messages appears:

Example errors:

• “Update failed” — an error occurred during the update
• “Hash verification failed” — the downloaded data is corrupted
• “Protocol error” — an error occurred during communication
• “Invalid firmware signature” — signature verification failed
• “Invalid OTA data” — the received data is malformed

You may also see this error before the update starts:

• “OTA rejected: UI busy” — the device is asleep, showing a PIN entry screen, or showing a dialog. Touch the device to wake it, clear whatever is on screen, and start the update again (see 12.2, “When an update can be started”)

What to do:

1. Restart the device
   • Power off, then on
2. If it still fails
   • Switch to USB
   • If you are on BLE, improve the radio conditions

▲ Important: even if an update fails, your wallet data is unaffected (it is safe).

12.7 Checking the current version

Check the current version under “Settings” → “About.”

ℹ Tip: updating regularly keeps you on the latest features and security.

13. Troubleshooting

13.1 Frequently asked questions

Q1: I forgot my PIN

A: You can recover if you have your recovery phrase.

1. Perform a factory reset
   • “Settings” → “Factory Reset”
2. Restore the wallet
   • “Wallet” screen → “Create Wallet” → “Restore”
   • Enter your recovery phrase

▲ Warning: without your recovery phrase, you lose your assets.

Q2: The screen is unresponsive or frozen

A: Restart as follows.

1. Power off with the power button
2. Press the power button again to start up

ℹ Tip: this resolves almost every problem.

Q3: The QR code will not scan

A: Check the following.

• Screen brightness: turn up your monitor’s brightness
• Distance: adjust the distance between Openloop and the monitor (15–30 cm recommended)
• Angle: change the angle to avoid reflections
• QR code size: enlarge it in Sparrow Wallet or similar

ℹ Tip: when a QR code has several frames, wait for it to cycle through automatically.

Q4: The USB or BLE connection keeps dropping

Over USB:

• Check that the cable is properly connected
• Try a different USB port
• Replace the cable (it may be faulty)

Over BLE:

• Move the device and your phone closer together
• Re-check your Bluetooth settings
• Remove the pairing and connect again

Q5: I lost my recovery phrase

A: Unfortunately, there is no way to recover it.

▲ Worst case: if the device breaks, your assets are lost forever.

What to do right now:

1. Display the recovery phrase again: “Wallet” screen → “Recovery Phrase”

2. Make several copies: paper plus a metal plate

3. Store them in different places

ℹ The lesson: your recovery phrase is your assets. Guard it carefully.

13.2 Error messages and what to do

“Wrong PIN!”

Cause: the PIN is incorrect.

What to do:

• Enter it again carefully
• After 10 failures the device erases all data (the number of remaining attempts is shown)

“No wallet”

Cause: no wallet has been created.

What to do:

1. Create one: “Wallet” screen → “Create Wallet” → “Generate”
2. Restore one: “Wallet” screen → “Create Wallet” → “Restore”

“Wallet Corrupted”

Cause: when this appears on a device that has no wallet yet (first power-on, or just after “Erase Wallet”), it is a false alarm from a defect in v1.1.0 and earlier, not a fault. Fixed in v1.1.1 — from v1.1.1 on, the “Welcome to Openloop” dialog appears as it should.

What to do:

• The choices are the same as the “Welcome to Openloop” dialog. Just choose “Generate” or “Restore” (see 2.3)
• Updating to v1.1.1 or later stops it appearing (see chapter 12)

▲ If it appears suddenly on a device with a wallet you were using, it may not be a false alarm (see 8.4).

“Pairing failed” (BLE)

Cause: Bluetooth pairing failed.

What to do:

1. Check the BLE setting: “Settings” → “BLE” → ON

2. Re-check the pairing code: do the six digits match?

3. Pair again: “Unpair” → “Start pairing”

“Update failed” (OTA)

Cause: the firmware update failed.

What to do:

1. Restart the device

2. Switch to USB (if you were on BLE)

3. Try the update again

ℹ Tip: your wallet data is unaffected (it is safe).

“Invalid mnemonic” (when restoring)

Cause: the recovery phrase is wrong.

What to do:

• Check the spelling against the BIP39 word list
• Check the order: first word, second word, and so on
• Check the count: 12 or 24 words

13.3 Factory Reset

What a factory reset does

It erases all data and returns the device to its initial state.

▲ Warning: this cannot be undone.

Data that is deleted:

• The wallet (private keys, recovery phrase)
• The PIN
• Settings (language, sound, network, and so on)
• BLE pairing data
• FIDO2 passkeys (HMAC key, seed, all entries)
• PIV key pairs and certificates (all four slots)
• The PIV PIN

Data that is not deleted:

• The firmware version

▲ About recovery: your wallet’s crypto assets can be restored from your recovery phrase. However, FIDO2 passkeys and PIV keys cannot be restored. Passkeys must be registered again at each service, and PIV keys must be regenerated with new certificates issued.

How to perform a factory reset

Step 1: Confirm your backup

▲ Essential: check the following.

• My recovery phrase is backed up
• I have moved all my assets (or I plan to restore)

Step 2: Run the factory reset

1. “Settings” → “Factory Reset”
2. Review the warning

<span class="symbol warn">▲</span> Warning: danger zone

The following will be completely erased:
- Recovery phrase (mnemonic)
- PIN
- All settings
- All wallet data

This cannot be undone!

[Erase All] [Cancel]

3. Tap “Erase All”
4. Enter your PIN (final confirmation)
5. The erase runs
   • “Please wait…” is displayed
   • It finishes in a few seconds

Step 3: Back to the initial state

• The device restarts
• It is in the same state as on first boot
• You need to create or restore a wallet

Done: the device has been returned to factory condition.

When you might need a factory reset

• ★ You forgot your PIN (and plan to restore from your recovery phrase)
• You are giving the device to someone else
• You want to clear out a test wallet
• You want to reset your settings

13.4 Recovery mode (recovery firmware)

What recovery mode is

Recovery mode is an emergency feature that starts automatically or manually when the main firmware becomes corrupted and will not boot. Recovery firmware stored in a separate partition starts up, letting you reinstall the main firmware over USB or BLE.

Characteristics of recovery mode:

• A dedicated partition: stored in a “factory” partition separate from the main firmware
• Firmware update: you can reinstall the main firmware through Openloop Connect
• ★ Wallet data is protected: your wallet data is preserved even in recovery mode
• Settings: you can change the language, USB, BLE, and pairing settings

How to enter recovery mode

1. Power the device off
2. Hold the power button down until it powers on and the startup tone plays
3. Release the power button as soon as you hear the tone

▲ Important: release within 3 seconds of the tone. Too late and it boots normally.

ℹ Tip: the trick is to use the tone as your cue. Even if the volume is set to zero, the timing is judged internally in exactly the same way.

The recovery mode home screen

In recovery mode you see the following information and buttons:

Information shown:

• The recovery firmware version
• USB connection status
• BLE connection status

Buttons:

• Boot Main: returns to the main firmware. Tap this if you entered recovery mode by accident (if the main firmware cannot be read, it shows “No FW” and the button is disabled)
• Settings: opens the settings screen for language, USB, BLE, and pairing

▲ Note: if the main firmware is corrupted, tapping “Boot Main” may return you to recovery mode. In that case you need to reinstall the firmware.

The recovery mode settings screen

You can change the following on the settings screen:

• Language: Japanese / English
• USB: ON / OFF
• BLE: ON / OFF
• Pairing: start pairing / unpair

ℹ Tip: even when the main firmware will not boot, you can turn USB or BLE on from the recovery mode settings screen and then connect and update with Openloop Connect.

Updating firmware in recovery mode

Supported transports:

• USB: over USB Type-C
• BLE: over Bluetooth Low Energy

How to update:

1. Boot into recovery mode
2. Turn USB or BLE on in the settings screen (if needed)
3. Launch Openloop Connect and connect the device
4. Openloop Connect shows the latest firmware — run the update
5. The device restarts automatically and boots the main firmware

▲ Note: do not power the device off during a firmware update.

14. Supported Crypto Assets and Networks

14.1 Bitcoin (BTC)

Supported networks

Address formats (examples)

• Legacy (P2PKH): 1... (BIP44)
• Nested SegWit (P2SH): 3... (BIP49)
• Native SegWit (Bech32): bc1q... (BIP84)
• Taproot (P2TR): bc1p... (BIP86) ▲ Address display only. Signing is not supported
• Testnet: tb1q... and so on

HD derivation path

• Standard path (example): m/84'/0'/0'/0/0 (BIP84: Native SegWit)
• Depending on the script type you can also choose m/49' (Nested SegWit), m/44' (Legacy), or m/48' (multisig) — see 4.1

▲ Taproot (m/86') cannot be signed. If you create a Taproot account in your companion wallet, the signing confirmation screen shows “Cannot sign: Taproot (P2TR) is not supported” and the “Sign” button is disabled.

ℹ Tip: compatibility with Sparrow Wallet is excellent.

ℹ For details of the confirmation screen, see “6.7.1 Bitcoin (BTC).”

14.2 Ethereum (ETH)

Supported networks (215 chains: 129 mainnets + 86 testnets)

Openloop supports every EVM chain on which a CoinGecko Top 1000 token exists.

Support at a glance:

Broadly, this covers Ethereum and its layer 2s, alternative layer 1s (BNB Smart Chain, Avalanche, and so on), ZK rollups, and emerging chains. For the complete list of built-in network names, see “15.7 Built-in EVM networks.”

Major networks:

Other supported networks (excerpt):

ℹ Tip: for the list of built-in networks, see “15.7 Built-in EVM networks.”

About networks that are not built in:

• EVM networks outside the list above can still be signed for
• The signing confirmation screen shows something like “Chain ID 12345” instead of a name, and the currency symbol for the amount and fee becomes “ETH?”
• Check the network information in your companion wallet before signing

Address format

• All: 0x... (20 bytes of hex)

HD derivation path

• Standard path (example): m/44'/60'/0'/0/0 (BIP44: Ethereum)

ERC-20 token support (2,599 tokens)

Coverage: the CoinGecko top 1000 tokens by market capitalization (2,599 entries including multi-chain deployments)

Supported tokens at a glance:

Important characteristics:

• A shared address: ETH and ERC-20 tokens use the same address (0x...)
• Gas is required: fees for ERC-20 transfers are paid in ETH
• Network-dependent: the same token name on a different network is a different token (for example, mainnet USDT and Arbitrum USDT are different)
• Multi-chain: many tokens are deployed on several chains

Rough fees by network (as of 2025):

Major token examples:

ℹ Tip: for the list of built-in tokens, see “15.8 Built-in ERC-20 tokens.”

About tokens that are not built in:

• ERC-20 tokens outside the list above can still be signed for
• The signing confirmation screen shows “ERC-20 Token” or “Unknown ERC-20” instead of a name, together with the warning “Unknown token - verify contract!”
• The contract address is displayed, so compare it with your companion wallet

ℹ Note: check the contract address before sending, and confirm it is not a scam token.

ℹ For details of the confirmation screen, see “6.7 The signing confirmation screen in detail.”

Detailed instructions:

• Receiving: 5.6 Receiving ERC-20 tokens
• Sending: 6.6 Sending ERC-20 tokens

14.3 XRP (Ripple)

Supported networks

Address format

• Classic Address: r...

ℹ Note: X-Address is not supported at present.

Destination tag support

Supported: the destination tag required when sending to an exchange is displayed.

ℹ For details of the confirmation screen, see “6.7.4 XRP (Ripple).”

HD derivation path

• Standard path for Ed25519: m/44'/144'/0'/0'/0' (BIP44, all levels hardened)
• Standard path for secp256k1: m/44'/144'/0'/0/0 (BIP44)

▲ For XRP the derivation path changes with the curve you select. Set the curve on the “Connect Wallet” screen (see 4.1).

14.4 Solana (SOL)

Supported networks

Address format

• A Base58-encoded 32-byte public key (for example 7xKXtg...)

HD derivation path

• Receive screen default: m/44'/501'/0' (three levels)
• Used when signing: m/44'/501'/0'/0' (four levels)
• Both are SLIP-0010 (all levels hardened, Ed25519)

Supported signature types

• Transaction signing
• Off-chain message signing

Connection methods

14.5 TRON (TRX)

Supported networks

Address format

• Base58Check encoded, starting with T (for example TJYs...)

HD derivation path

• Standard path: m/44'/195'/0'/0/0 (BIP44: TRON, secp256k1)

Connection methods

▲ TRON does not support Air Gap (QR codes). Use a USB connection for TRON.

15. Appendix

15.1 Glossary

Hardware wallet

A wallet that keeps private keys safely on a dedicated device. Because it is isolated from the internet, it is largely immune to malware.

Recovery phrase (mnemonic)

A list of 12 or 24 English words. The only way to restore a wallet. Your most important asset.

PSBT (Partially Signed Bitcoin Transaction)

An unsigned Bitcoin transaction. The standard format for signing with an air-gapped wallet.

Air Gap

A method that isolates a device completely from the internet, exchanging data through QR codes. The highest level of security.

HD key derivation (Hierarchical Deterministic Key Derivation)

The technique of generating many addresses hierarchically from a single seed (recovery phrase) — BIP32/BIP44/BIP84.

Mainnet

The production blockchain network where real crypto assets circulate.

Testnet

A blockchain network for development and testing, where you can practise with worthless coins.

BBQr

A format that splits large data across several QR codes for transmission. Optimized for Bitcoin PSBTs.

UR (Uniform Resources)

A general-purpose QR code format, expected to be adopted by many wallets.

BIP32

The standard for HD (hierarchical deterministic) wallets. It lets you generate many addresses from one seed by specifying a derivation path (for example m/84’/0’/0’/0/0).

BIP39

The standard for recovery phrases, whose words are drawn from a list of 2,048 English words.

BIP44 / BIP84

Standards for address derivation paths. BIP44 is used for the traditional format (P2PKH); BIP84 for Native SegWit (bc1…).

BLE (Bluetooth Low Energy)

The low-power Bluetooth standard, used to connect to phones.

OTA (Over-The-Air)

Firmware updating over a wireless connection.

ERC-20

The token standard on Ethereum (USDT, USDC, and so on).

FIDO2 / CTAP2

A secure authentication standard that replaces passwords, enabling passwordless sign-in to web services. CTAP2 (Client to Authenticator Protocol 2) is the protocol between the device and the browser.

Passkey

An authentication credential based on FIDO2. A unique key pair is generated for each service and stored safely on the device.

PIV (Personal Identity Verification)

The US government’s smart card authentication standard, used for SSH authentication, PDF signing, TLS client authentication, and more.

PKCS#11

The standard interface to cryptographic tokens (smart cards, HSMs, and so on). Openloop uses it to reach the PIV features.

Openloop Connect

Openloop’s companion application, available for desktop (Windows/Mac/Linux) and mobile (iOS/Android). For PIV/PKCS#11 it works with the PKCS#11 library over WebSocket.

Destination tag

An optional identifier used when sending XRP. Required when sending to an exchange.

15.2 Supported wallet software

For Bitcoin

For Ethereum / ERC-20

For XRP

For Solana

For TRON

ℹ About compatibility: Openloop uses the Ledger-compatible protocol over USB and BLE, and the KeyStone-compatible protocol over QR codes. Ledger-compatible applications other than Ledger Live, and KeyStone-compatible applications, generally work.

15.3 Technical specifications (summary)

Hardware

• Processor: ESP32-S3 (dual-core Xtensa LX7, running at 160 MHz)
• Memory: 8 MB PSRAM, 16 MB flash
• Display: 320×240 pixel IPS LCD (touchscreen)
• Secure element: NXP SE050 (EAL 6+ certified)
• Connectivity: USB-C / Bluetooth 5.0 (BLE) (Wi-Fi hardware is present but the firmware never uses it)
• Camera: GC0308 (for scanning QR codes)
• Battery: 450 mAh lithium polymer (built-in)

Software

• Firmware: based on ESP-IDF 5.4
• UI: LVGL 9.x
• Cryptography: mbedTLS, SE050
• Standards: BIP32/BIP39/BIP44/BIP84, EIP-55, SLIP-0044
• FIDO2/CTAP2: ES256 (P-256), EdDSA (Ed25519), up to 100 resident keys
• PIV: P-256, Ed25519, RSA-2048, four slots (9A/9C/9D/9E)

15.4 Third-party libraries

Libraries used

Openloop uses well-established third-party libraries:

You can see the details under “Settings” → “About.”

15.5 Tutorial: Sparrow Wallet (Bitcoin Air Gap)

This tutorial walks through pairing Sparrow Wallet with Openloop over Air Gap (QR codes) and sending Bitcoin.

What you need:

• An Openloop with a wallet created
• A PC with Sparrow Wallet installed
• An internet connection (for the PC only)

Step 1: Export the xpub from Openloop

1. On Openloop, tap “Wallet” → “Connect Wallet” → “Bitcoin”
2. The QR code appears

Step 2: Create the wallet in Sparrow Wallet

1. Launch Sparrow Wallet
2. “File” → “New Wallet” → enter a wallet name
3. Choose “Airgapped Hardware Wallet”
4. Click “Scan…” and scan the QR code on Openloop

5. Once the xpub is read, click “Apply” → “Save”

Step 3: Build the transaction

1. Select the “Send” tab in Sparrow Wallet
2. Enter the destination address and the amount
3. Click “Create Transaction”
4. Click “Finalize Transaction for Signing”
5. Click “Show QR” to display the PSBT QR code

Step 4: Sign the PSBT on Openloop

1. Tap “Send” on Openloop
2. Tap “Scan QR”
3. Scan the PSBT QR code shown in Sparrow
4. Review the transaction details
5. Tap “Sign” (right) to sign
6. The signed PSBT QR code appears

Step 5: Read the signed PSBT back into Sparrow

1. Click “Scan QR” in Sparrow Wallet
2. Scan the signed QR code on Openloop
3. The signature is verified

Step 6: Broadcast

1. Click “Broadcast Transaction”
2. The transaction is sent to the network
3. Check it on the “Transactions” tab

Done: the Bitcoin transfer is complete.

15.6 Tutorial: Safe (Ethereum USB)

This tutorial walks through pairing Safe (a multisig wallet) with Openloop over USB and sending Ethereum.

What you need:

• An Openloop with a wallet created and USB enabled
• A PC with Chrome, Brave, or Edge
• A USB-C cable
• An internet connection

Step 1: Turn on USB on Openloop

1. On Openloop, tap “Settings” → “USB”
2. Set USB to “ON”
3. Connect to the PC with a USB-C cable

Step 2: Add the account in Safe

1. Go to app.safe.global
2. Click “Connect Wallet”
3. Choose “Ledger” (Openloop is Ledger-compatible)
4. Choose the “Ledger Live” path

5. When the address confirmation appears on Openloop, tap “Approve”
6. The address is added as a Safe owner

Step 3: Build the transaction

1. Click “New Transaction” in Safe
2. Choose “Send tokens”
3. Enter the destination address and the amount
4. Click “Next” → “Execute”

Step 4: Sign on Openloop

1. The transaction confirmation screen appears on Openloop
2. Check the destination, amount, and fee
3. Tap “Sign” (right) to sign

Step 5: Execute the transaction

1. Safe confirms the signature
2. Once enough signatures are collected, it broadcasts automatically
3. “Transaction was successful” appears

Done: the transfer from Safe is complete.

15.7 Built-in EVM networks

Openloop supports every EVM network. The list below covers the built-in networks (215 chains) whose names are displayed on the device screen.

ℹ Note: EVM networks not in this list can still be used. In that case the chain ID is displayed instead of a network name.

EVM mainnets (129 chains)

EVM testnets (86 chains)

15.8 Built-in ERC-20 tokens

Openloop supports every ERC-20 token. The summary below covers the built-in tokens (2,599 entries) whose names and symbols are displayed on the device screen.

ℹ Note: ERC-20 tokens not in this list can still be used. In that case the contract address is displayed instead of a token name.

Token data source

• Source: the CoinGecko API (top 1000 by market capitalization)
• Multi-chain deployments: where the same token is deployed on several chains, each deployment is registered as its own entry
• Decimals verified: decimals were verified against Uniswap/1inch/CoinGecko for 99.6% of tokens

Tokens by category

ℹ The per-category counts are rough approximations. Category is not stored in the token data, so the total does not match the number of registered entries (2,599).

Token deployments on major chains

The token record

Each token entry contains the following:

Cautions

1. Watch for duplicate symbols: the same symbol on a different chain is a different contract
2. Verify the official address: always check the official contract address before sending
3. Beware of scam tokens: scam tokens imitating well-known ones exist
4. Check the network: always select the correct network when sending

Closing

Thank you for choosing the Openloop hardware wallet.

We hope this manual helps you manage your crypto assets safely and comfortably.

Three things to remember:

1. ★ Guard your recovery phrase carefully
2. Practise on testnet before using mainnet
3. When something is unclear, check the manual

Enjoy managing your crypto assets safely.

Haudi Crypto, Inc. — Openloop development team Version 1.1.1 | 2026-08-13

© 2026 Haudi Crypto, Inc. All rights reserved.