Coldcard Mk4
1 storyThe transaction-signing design of Coldcard Mk4 uses dual secure element chips, microSD air-gapped signing, and NFC transaction transfer. Users encounter physical numeric keypad, USB-C connectivity, BIP39 backup support, and Coldcard firmware when initializing the wallet, verifying transactions, or restoring access. Use Coldcard Mk4 for hardware design, firmware, transaction confirmation, recovery, companion-software support, security research, and model-specific compatibility. Shared software belongs under its product entry, while model-specific changes remain with Coldcard Mk4.
Coldcard Firmware Bug Drains $89M From Bitcoin Wallets
A March 2021 Coldcard firmware flaw let attackers steal about 1,367 BTC worth roughly $89 million from thousands of addresses. Researchers say vulnerable wallets remain at risk and urge immediate fund moves