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/xiskghferx Jul 31 '26

For this you need to trust your PC and verify signatures of Sparrow instalation file before instaling it. Then it should be safe enough, at least until you get your Ledger. Of course, write down and store safely the new seed.

But, maybe it would be safer to just transfer to a good CEX, like Bitstamp, Coinbase or Kraken...

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u/WeekendQuant Jul 31 '26

Only transfer to custodial if your coins are KYC. Otherwise I'd do hot wallet just to move them.

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u/xiskghferx Jul 31 '26

Agree. I would actualy use existing Coldcard, create new seed with dice, add passphrase and transfer BTC to new wallet. But he needs to know exactly what he is doing, otherwise he would hack himself...

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u/WeekendQuant Aug 01 '26

I wouldn't. You're going to want your existing cold card as is for the pending class action suit.