Coinkite COLDCARD Mk5

Start with the named Mk5 setup guide.

1. 1
   Inspect the bag and match its identifier with the device, then set the PIN on Mk5. The PIN has two parts of 2–6 digits each. After the first part, the device shows its anti-phishing words; check those before entering the second part at later logins.
2. Verify firmware before any seed or restoreWith the PIN set, stop before selecting a seed or restore option. Verify the signed firmware release manifest and the firmware file’s SHA-256 hash, install the current recommended standard release, then confirm the installed version. Updates require the PIN. Do this before generating or importing a seed, restoring a backup or funding the wallet.
3. 3
   For a new BIP39 wallet, choose 12 or 24 words. Current standard firmware requires one method of adding your own randomness before the final words appear: at least 65 key presses with irregular timing, 50 fair, independent rolls of a physical six-sided die or 128 fair, independent flips of a physical coin. Follow the actual input procedure and keep those inputs private and unrecorded. Write the final words in order on paper or metal, keep that record private and offline, and complete the device’s word quiz. Advanced Dice Rolls Only is a different procedure.

To restore existing words, the documented import accepts English BIP39 phrases of 12, 18 or 24 words. Use the intended wallet’s actual account rules and any exact passphrase when rebuilding it. For this word-and-passphrase route, the exact original value must fit Mk5’s 100-character ASCII input limit; do not alter it to fit. The word format alone does not identify every account. A later power cycle checks that your recorded PIN and anti-phishing words work as expected.

An optional BIP39 passphrase combines with the seed words to open a different wallet with its own addresses. A different value, including a typo, opens another wallet. Funds do not move automatically from the base wallet to the passphrase wallet. Mk5 accepts at most 100 ASCII characters: letters without accents, numbers and symbols. Ordinary word-and-passphrase restoration requires the exact original value to fit; do not alter it to fit.

Coinkite recommends a strong, unique passphrase for a balance whose loss would materially harm you. That adds a recovery responsibility: keep the exact value separately from the seed words and record the wallet fingerprint. Check the same fingerprint after a power cycle and re-entry, then test the complete recovery process before funding. The fingerprint is the wallet identifier you compare to check that you opened the intended wallet.

Enter and confirm the passphrase on the Mk5 keypad. Apply it before exporting that wallet to Sparrow or creating its backup. The separately documented advanced ckcc method can send it from a trusted desktop through an encrypted USB protocol and still confirms on-device; this is a specific command-line option, not a general companion-app entry method.

Sparrow on Windows, macOS or Linux watches the public account exported from Mk5. That export describes the public key, account derivation path and address type; it does not import the seed into Sparrow. Sparrow shows balances and prepares payments, while Mk5 supplies the signature.

After verifying the address below, copy the checked Bitcoin address. Share it with another payer, or follow the transfer guide before approving your own withdrawal from a wallet or exchange.

• Check receiving details and your transfer before approval 

Use the maker’s microSD export procedure for the wallet you intend to use. If a passphrase is active, the export describes that wallet; the base wallet needs a separate export and Sparrow wallet. After import, compare the full receiving address in Sparrow with the matching address in Mk5’s Address Explorer before funding.

Once verified, that address can receive an ordinary Bitcoin payment while Mk5 is unplugged. The network records the payment; receiving it does not require a signature from Mk5 or keeping the device awake.

The maker also documents adding an initialized Mk5 wallet to Sparrow and signing Bitcoin transactions over USB, with Mk5 unlocked, USB data enabled and a data-capable USB-C cable. USB-C power and that live data connection are different jobs. The microSD routine described here does not require enabling USB data.

Use Nunchuk on a compatible NFC-capable iPhone or Android phone with a Mk5 that is already initialized, powered and unlocked. Enable NFC Sharing on Mk5 and import the intended wallet’s public account into Nunchuk before signing. This documented route assumes setup is complete; it does not establish fresh Mk5 setup through the phone.

Get the recipient’s current receiving details through a trusted source first; use the guide to check the transfer before approval.

• Check receiving details, approval and a small test 

1. Build and check the payment in Nunchuk.
2. Before transferring the request by NFC, choose Advanced/Tools → NFC Tools → Sign PSBT on Mk5. Then transfer the request by NFC.
3. Review the full recipient address, amount and fee on Mk5. If anything differs or is unclear, cancel; otherwise confirm the signature.
4. Transfer the signed result back to the phone and broadcast from Nunchuk.

The NFC exchange is not network confirmation.

If the tap does not register, check that NFC Sharing is enabled and hold the phone’s NFC area flat near Mk5’s top-right corner, steady for a few seconds. The linked official guide also covers a missing NFC export option and a wrong-wallet warning. Numerical phone OS requirements for this workflow remain unconfirmed.

For a BIP39 wallet, keep the seed words as the base wallet’s recovery material. A BIP39 passphrase is a separate secret if you use one. The device PIN unlocks Mk5; it does not restore these keys on a replacement. For ordinary word-and-passphrase restoration, the exact original passphrase must fit Mk5’s 100-character ASCII input limit; do not alter it to fit.

A forgotten Mk5 PIN cannot be recovered. Coinkite documents thirteen failed attempts before permanent device bricking, so trying more PINs is not a recovery method. A lost or unusable device does not erase Bitcoin on the blockchain; restoring access depends on the saved recovery material for the intended wallet.

Check the recovery method you will rely on

• File integrity is not a restoration testVerify Backup performs a CRC32 integrity check without decrypting the file. It can detect file damage, but it is not a complete restoration test or cryptographic proof that the file is authentic.
• Follow the restoration procedure and compare the walletUse the manufacturer’s restoration procedure and compare the expected wallet fingerprint. For MS1, keep the original wallet and backup intact while testing enough combinations of your recorded shares to include every share you will keep. Each recovered wallet must have the original fingerprint and reproduce a known receiving address using the same network, address type, derivation path and wallet configuration.
• Keep your working wallet while you checkRestoring a backup as the Master Seed requires a COLDCARD with no Master Seed, or a deliberate wipe of its existing Master Seed. The maker separately documents testing a backup as a Temporary Seed without wiping the Master Seed. Do not erase your only working wallet to investigate a problem: follow the complete maker procedure with verified recovery records.

Cloning copies an existing wallet; it is not the advisory’s migration to a new independent seed.