COLDCARD Mk4 Firmware v5.1.1: MicroSD 2FA, Tapsigner Import, and More

Coldcard is a Bitcoin hardware wallet, it signs transactions to keep the private keys offline.

New Features

“MicroSD card as Second Factor”. Specially marked MicroSD card must be already inserted when (true) PIN is entered, or else seed is wiped. Add, remove and check cards in menu: Settings -> Login Settings -> MicroSD 2FA
Import TAPSIGNER encrypted backup as main or ephemeral seed, for PSBT signing. This is a great way to safely use the key previously held inside a TAPSIGNER, because the COLDCARD can take over the signing that used to be done by the card.
Detached Bitcoin signature files for most exports.

Full Blog Post and Download Link

No Bullshit Bitcoin is funded by donations. Click here to support us.

Author:

No Bullshit Bitcoin

Get our newsletter and most important updates directly to your inbox.

No spam. Unsubscribe anytime.

COLDCARD Disaster: Weak Entropy Bug Enables Drain of Funds from Seeds Generated Since 2021

A build error present in COLDCARD firmware for more than five years made seeds generated on affected devices predictable, enabling attackers with no access to the hardware to reconstruct private keys offline and sweep the matching addresses.

03 Aug 2026

7 min read

Ashigaru Whirlpool and Terminal v1.0.0 Released

Ashigaru Whirlpool is a ZeroLink coinjoin implementation designed to sever all deterministic links between inputs and outputs, ensuring enhanced bitcoin transaction privacy.

23 Jun 2025

3 min read