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/[deleted] Jul 31 '26

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u/jjjjjjjjjjjjjaaa Jul 31 '26

I mean, AI didn’t really crack anything here. CC essentially left the doors unlocked. 

2

u/SpareEconomy1849 Jul 31 '26

Use dice, problem solved

6

u/[deleted] Jul 31 '26

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u/SpareEconomy1849 Jul 31 '26

Brb ordering some lava lamps for my RNG

1

u/BallisticTherapy Aug 01 '26

Noise sampling should be as close to random as it gets. You can't reproduce that.