Hardware wallets

Coldcard Mk5

Bitcoin-only hardware wallet built for air-gapped signing with a microSD card or NFC. Successor of the Mk4, fully backwards compatible.

Official Coldcard Mk5 websitearound $219

What is Coldcard Mk5?

Coldcard Mk5 is a Bitcoin-only hardware wallet made by Coinkite. The maker’s page says it uses two Secure Elements from different vendors, names Microchip’s ATECC608 and Maxim’s DS28C36B as the chips that store the master seed, and lists MicroSD, NFC, USB-C and Virtual Disk workflows. There is no Coldcard account and no required companion app, so you pair it with wallet software of your choice. Compared with the Mk4, the Mk5 has a new 1.54-inch Gorilla Glass display, a redesigned keypad, the USB-C port on the bottom, a tougher case and faster NFC; it runs exactly the same firmware image as the Mk4. The maker’s page lists it at $219. This page describes the Mk5; the Coldcard Q is a separate product.

Key facts

Type
Hardware
Made by
Coinkite, Canada
Works with
Windows, macOS, Linux, Android, iOS
Keys
You hold the keys
Bitcoin-only
Yes
Source code
Partly openSource code is public under MIT with the Commons Clause, which does not grant the right to sell the software.
Lightning
No
Multisig
Yes
Air-gapped
Yes, signs without a cable connection
Experience
Advanced
Price
around $219

Details last checked on the maker's website: . How we compare

Good for

  • Air-gapped signing, the device never has to touch a computer
  • Multisig setups and experienced users who want every option

Watch out

  • Coldcard's security status page (checked 2026-10-19) says a firmware bug weakened seed generation in versions from 2021 to July 2026. Seeds generated on affected firmware, including Mk4, Mk5 and Q, should be migrated to a new seed, because updating the firmware does not repair an existing seed. Fixed releases start at 5.6.0 (Mk4, Mk5) and 1.5.0Q (Q), and the page recommends 5.6.3 and 1.5.3Q. See coldcard.com/security/status
  • Steep learning curve and a very technical interface
  • No companion app of its own, you pair it with Sparrow, Electrum, Nunchuk or similar

Coldcard Mk5 features

PIN options. The PIN has two parts of 2 to 6 digits each, and the first part determines the anti-phishing words shown at login. The maker’s page describes a duress PIN that opens a separate wallet, a Brick Me PIN that destroys the dual secure element, and a login countdown with a forced delay. The quick start warns that no one can help you if you forget your PIN. Offline signing. For fully offline use, transactions move by microSD card: the device signs them and saves the result to the card. The quick start says the device only needs power over USB-C, not data, and stays hidden from a connected computer until the PIN is entered. NFC can also carry files, and PushTX lets an NFC-enabled phone with internet access broadcast a signed transaction. Multisig. The documentation says Coldcard supports M-of-N wallets with up to 15 co-signers. You import the wallet from a microSD file, a Virtual Disk or NFC, and each Coldcard adds one signature per pass. The maker’s page also lists Co-Signing, which creates automated multisig wallets protected by user-defined spending policies. Seed generation and backups. Each new seed combines fresh device entropy with one required method: 65 key presses, 50 dice rolls or 128 coin flips. The documentation recommends dice rolls and a strong, unique BIP-39 passphrase for wallets that hold significant value. The maker also lists Seed XOR and a Seed Vault, and the documentation covers encrypted backups. Works with wallet software. The documentation lists Nunchuk, Sparrow, Bitcoin Core, Electrum, BlueWallet, Casa, Cove, Fully Noded, Specter Desktop, Unchained, Wasabi Wallet, Coldcore and Theya as compatible, and says any wallet that follows BIP-174 (PSBT) should be compatible.

Security and custody

Coldcard publishes its firmware, simulator, bootloader and hardware schematics on GitHub, and the README describes how to rebuild a release and get exactly the same bytes as the device binary. The licence is the MIT licence with the Commons Clause, which says the grant of rights does not include the right to sell the software, where selling includes providing a paid product or service whose value comes substantially from it. At startup the firmware signature is checked and a green or red light shows the result. Coldcard’s security status page, last updated 2026-10-01, says a firmware bug weakened seed generation, and the README says versions from 2021 to July 2026 had a bug that produced poor entropy. According to the status page, attackers regenerated affected private keys offline; the devices themselves were not taken over remotely. Seeds generated on affected firmware, including on the Mk4, Mk5 and Q, should be migrated to a new seed, because updating the firmware does not repair an existing seed and a BIP-39 passphrase does not either. The first fixed release for the Mk4 and Mk5 is 5.6.0, and the page recommends 5.6.3. The page makes an exception for seeds where at least 50 fair, private dice rolls were added with the Add Dice Rolls workflow; the migration guide at coldcard.com/security/migrate sets the exact conditions.

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Coldcard Mk5 FAQ

What is new in the Coldcard Mk5 compared with the Mk4?

According to Coldcard, the Mk5 has a new 1.54-inch Gorilla Glass display, a redesigned keypad, the USB-C port on the bottom, a tougher case and faster NFC. It runs exactly the same firmware image as the Mk4, and the two secure elements are unchanged.

Does the Coldcard Mk5 need an app?

No required app. The maker's page says there is no Coldcard account or required companion app. You use wallet software such as Sparrow, Electrum or Nunchuk, which the documentation lists as compatible.

Does the Coldcard Mk5 support multisig?

Yes. The documentation says it supports M-of-N wallets with up to 15 co-signers, which you import from a microSD file, a Virtual Disk or NFC.

Is there a security notice for Coldcard seed generation?

Yes. Coldcard's security status page says a firmware bug weakened seed generation in versions from 2021 to July 2026. A seed generated on affected firmware, including on the Mk4, Mk5 and Q, should be migrated to a new seed, because updating the firmware does not repair it. Fixed releases for the Mk4 and Mk5 start at 5.6.0, and the page recommends 5.6.3. The details are at coldcard.com/security/status.

Guides

Sources

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