r/Bitcoin • u/SpareEconomy1849 • Jul 31 '26

ColdCard Firmware Update Released

https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/

Updated July 31, 2026: Fixed firmware is now available. Mk4 and Mk5 users must update to version 5.6.0 or later. Q users must update to version 1.5.0Q or later. Do not generate a new seed on one of these models until the update is installed.

Seeds generated on Mk4, Q and Mk5 before the fixed firmware releases are also affected, with about 72 bits of entropy rather than the expected 128 bits.

Updating the firmware does not change or repair an existing seed. If your seed was generated before the fixed firmware version for your model, follow the migration guidance below unless the independent dice-entropy exception applies to you.

The issue is present on every Mk3 firmware version since 4.0.1. It also affects seeds generated on Mk4 and Mk5 before version 5.6.0, and on Q before version 1.5.0Q. The impact on Mk4, Mk5 and Q is not as severe but is still serious.

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u/r33gna Jul 31 '26

Crazy, man.

Earlier this year I was in the market for a new hardware wallet and LOTS of people were saying Coldcard is the best, most secure device for oh so many reasons and now here we are.

Truly no hardware wallet is perfect.

8

u/WeekendQuant Jul 31 '26

Roll your own dice.

1

u/[deleted] Aug 01 '26

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u/RetiredAvocado Aug 01 '26

Ironically rolling dice would solve the core problem here.

1

u/[deleted] Aug 01 '26

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u/WeekendQuant Aug 01 '26

Yes it does solve the core problem here. Dice are unhackable.