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COLDCARD Firmware Update Introduces Codex32 and Shamir Backups

COLDCARD Firmware Update Introduces Codex32 and Shamir Backups

First seen 1 Oct 2026, 23:15 UTC • •
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ThreatCluster AI
ThreatCluster •October 2, 2026 at 05:06 UTC
  • •COLDCARD firmware 5.6.3 and 1.5.3Q released with Codex32 support.
  • •Codex32 allows splitting wallets into shares for enhanced recovery options.
  • •No funds are moved during the splitting process, maintaining wallet integrity.

On October 1, 2026, COLDCARD released firmware versions 5.6.3 and 1.5.3Q, introducing the Codex32 format for encoding wallet secrets and supporting Shamir Secret Sharing. This update allows users to split their wallet into shares, enhancing backup and recovery options. The Codex32 format, defined by BIP-93, enables users to create between 2 to 9 shares with a configurable threshold for recovery. The update does not move funds or change wallet keys. Users are advised to securely manage their shares and verify recovery processes. The firmware also includes optional Seed Vault names for temporary seeds and various signing and parsing fixes. No vulnerabilities or were reported in relation to this update.

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Timeline

2026-10-01
COLDCARD firmware update released
Firmware versions 5.6.3 and 1.5.3Q introduced Codex32 and Shamir Secret Sharing features.
Blog.Coinkite
2026-10-01
Codex32 guide published
A comprehensive guide on using Codex32 for encoding wallet secrets was made available.
coldcard.com

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Common questions

What is Codex32?
Codex32 is a format for encoding wallet secrets with built-in error detection and support for Shamir Secret Sharing.
How does Shamir Secret Sharing work?
It allows users to split a secret into multiple shares, requiring a certain number of shares to recover the original secret.
What should users do after the firmware update?
Users should review the new features, securely manage their shares, and test recovery processes to ensure functionality.