Upgrade Firmware

Current Version of Coldcard Firmware

Version 1.0.2 (Current)

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

Release Notes

Version 1.0.1 (Previous)

2018-09-05T1728-v1.0.1-coldcard.dfu built Sep 5th, 2018.

Release Notes

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

Background

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

advanced menu

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.