Coldcard Mk4 v5.0.7: Temporary Seed Signing, NFC Tools Menu, and More

Coldcard Mk4 v5.0.7: Temporary Seed Signing, NFC Tools Menu, and More

NFC Enhancements:

  • In older versions, multisig NFC import not offered if a MicroSD card was inserted, now this option provided Settings > Multisig Wallets > Import via NFC. NFC has to be enabled for this option to be visible in the menu.
  • NFC message signing (Advanced/Tools > NFC Tools > Sign Message). Send message in same format as Sign Text File over NFC, approve signing on Coldcard and send signed ASCII-armored message back over NFC.
  • Show address over NFC (Advanced/Tools > NFC Tools > Show Address).
  • Bugfix: Improved NFC commands exception handling
  • Bugfix: Share single address over NFC from address explorer menu.

HSM Enhancements:

  • Dynamic HSM Whitelisting. Foreign outputs can be attested-to by signing them with private key corresponding to the address specified in HSM policy. Attestation signature MUST be provided in PSBT in a new proprietary field.
  • HSM policy hash is now displayed during first activation and in the HSM status response. This enables fast comparison against known policy hashes.
  • Thanks to @straylight-orbit for above items!
  • Now ignores HSM commands over USB, by default. To enable and use HSM features, go to Advanced/Tools > Enable HSM > Enable

Other Changes:

  • New Feature: Ephemeral Seeds: Advanced/Tools > Ephemeral Seed (more info in docs/
  • Enhancement: New menu wraparound settings which allow you to scroll past top and bottom of any menu (Settings > Menu Wrapping).
  • Enhancement: Allow import of new descriptor type which specify both internal/external in single string (ie. ../<0;1>/..). We still export in older format.
  • Enhancement: add ability to specify address format in text file to be signed (3rd line of file)
  • Bugfix: Correct parsing of unknown fields in PSBT: they are now passed through.
  • Bugfix: Using lots of trick pins (7+), could lead to a case where the Coldcard would not accept the main pin, but trick pins continued to work. This release adds a workaround to avoid getting into that situation, and new units from the factory will ship with an updated bootrom (version 3.1.5).