Upgrade Firmware

Current Version of Coldcard Firmware

Learn how to upgrade here >

Version 1.1.0 (Current)

2018-11-26T1403-v1.1.0-coldcard.dfu built Nov 26, 2018.

Release Notes

• Allow setting max network fee to a number of possible levels, or disable it (was previously fixed to 10%). Thanks to @crwatkins for this suggestion.

• Touch improvements: two new setting, which are between the old 'Least Sensitive' and 'Most Sensitive' settings. New menu text.

• Touch sensitivity preference is applied before login, so PIN entry is easier.

• Although we do not use the bech32_decode() function recently found to have an buffer overflow bug, we've included the fix into our fork of the affected library. This change, and the original bug, does not affect the Coldcard firmware in any way.

• Correctly include witness data in transactions when signing based on witness UTXO data (thanks to @SomberNight)

• Bugfix: Fix divide-by-zero if transaction sends zero amount out (only possible if network fee equals 100% of inputs).

Version 1.0.2 (Previous)

2018-09-11T1428-v1.0.2-coldcard.dfu built Sep 11th, 2018.

Release Notes

• Add support for SLIP-132
  • yprv/zprv keys can now be imported
  • public.txt file includes both SLIP-132 and BIP-32 values where needed (segwit cases)
  • test cases added to match
• Can create Electrum skeleton wallet for Segwit Native and Segwit P2SH now.
  • caveat: the plugin is not ready yet for P2SH/Segwit, but Segwit native is fine
• Improvements in 'public.txt' output:
  • add SLIP-132 values where we can
  • correct names when used for Litecoin
• Improvements to backup and restore
  • can now restore cleartext backups (for devs only!)
  • fix "Unable to open ... /sd/backup.7z" error

Older releases, the source code, and much more be found in our repository on github.

How to upgrade

Advanced: Verify Your Downloads

The release binaries may be verified using this clear-signed text file and GPG. The command is:

gpg --verify signatures.txt

Please look for a signing key: 4589779ADFC14F3327534EA8A3A31BAD5A2A5B10

Don't forget to run SHA256 over the DFU files themselves, because that compares your actual file contents to what we signed.

Github.com is also protecting us because it verifies on all commits against the developer's public keys, and keeps a history of changes.

Background

The upgrade menu allows you to load updated firmware onto the Coldcard.

The menu allows loading an upgrade file from a MicroSD card, but it can also be done using the command line tool, or from the Electrum plugin.

Upgrade Functions

Show Version

Displays the version numbers that you have already.

From MicroSD

Select an upgrade file from MicroSD card and start the process.

Bless Firmware

Mark the contents of flash memory as "approved" and light the green "Genuine" light.

Upgrade Files

You need a DFU file for upgrades. It's about 690k in size and should have the extension .dfu.

The latest firmware will always be available in Github:

github.com/Coldcard/.../releases

All upgrade files must be signed by a Coinkite Inc. approved key, or the Coldcard will refuse to load and run them.

Bless Firmware

This command is not typically needed, but can be used to set the genuine/caution lights to green. Note that only the main PIN holder can do this. A normal firmware upgrade sequence does not require this action, but if the unit is powered down between installing the upgrade and the first successful login, then the light will be red and stays red until this command is used.

Downgrade Protection

In general, it may not be possible to downgrade (return to an older release). Some releases will set a "high water mark" so the bootloader that will block any downgrade to earlier versions. We will do this if a bug or security problem with an obsolete release is identifed.