Coldcard strengthens seed generation with firmware update
Coinkite released firmware 5.6.1 for Coldcard Mk4/Mk5 and 1.5.1Q for Coldcard Q to harden seed generation after a weakness in earlier randomness was linked to major losses. New seeds must now mix user-supplied entropy, including at least 65 keypresses with unpredictable timing, 50 die rolls, or 128 coin flips, with device randomness from secure elements and the hardware RNG. The goal is to keep keys unpredictable even if one entropy source fails. Coinkite urged immediate upgrades, warning that existing seeds remain vulnerable and should be replaced before funds are moved. The update also adds transaction re-verification before signing, stronger RNG checks, boot-time hardware-path verification, tighter USB restrictions, and blocks certain modifiable signature modes by default. Coinspect also launched Unlukey, a free tool to detect wallets possibly created from weak seed phrases.
