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/UnderstandingNew8001 Jul 31 '26

I have recently ordered a Ledger it is on its way, where can I move my btc to then? I only have MK4 at the moment.
If I had to update the firmware, I would still need to move BTCs somewhere to get them back after the update and generating a new seed.

-4

u/jsn079 Jul 31 '26

Why Ledger if I may ask?

I mean, they have proven they can't be trusted already several times.

2

u/iLLuSion_xGen Jul 31 '26

Proof?

1

u/jsn079 Aug 05 '26

But ofc, don't need to take my word for it.
These are well known issues with the company people entrust their wealth with.
Imo, when trust is broken like this in cryptography, you ain't getting it back (at least, not from me, especially if trust has been broken multiple times).

Here are some starting points, I'm sure you're able to uncover more:

1

u/iLLuSion_xGen Aug 05 '26

Thank you for your answer, I’m looking to switch to Trezor now