Coldcard Firmware Update Requires Affected Users to Move Bitcoin

Coldcard has released firmware updates to address a security flaw in its seed phrase generation process. The company warned users that those affected must create new wallets and move their Bitcoin.

The update, which covers Coldcard Mk4 and Mk5 devices with version 5.6.1 and Q devices with version 1.5.1Q, adds mandatory user entropy to the seed creation process. Users can now provide randomness through key presses, dice rolls, or coin flips supplied by the device owner.

Affected users must create a new wallet and transfer their Bitcoin before they can use their updated device. Coldcard advised users to verify the signed update before generating a replacement wallet and to record the replacement seed offline.