Thunderbolt: Validation failed or unknown device

Thunderbolt plugin validates the FW image compatibility with the controller being updated (both for Thunderbolt host controllers and Thunderbolt devices) before starting the flashing process. The exact compatibility check protocol depends on the HW type.

The plugin tries to be as future-compatible as possible, so it tries to run the same existing compatibility tests even for newer, unknown devices (not including host controllers). If the test passed, there is a good chance that the image is compatible with the device, but it's impossible to foretell that this will be the case for all future devices. Thus, by default the operation fails with the following error:

firmware validation seems to be passed but the device is unknown

If a FW update is still desired considering this, you can enforce the update by explicitly providing the --force argument to the command line. So if you were updating the Thunderbolt controller with the # fwupdmgr update command you would instead run: # fwupdmgr update --force

Please note: this flag overrides the validation not only for the case described above but also for all cases where the validation failed. Those other cases are much less safe to override, so make sure you don't have other errors besides the one you decided to override.

Are you updating ThinkPad X1 Carbon Gen6 Thunderbolt Controller?

Before update, set the Thunderbolt BIOS Assist Mode to "Disable" in BIOS setup under Config > Thunderbolt 3. DO NOT FORCE UPDATE Thunderbolt Controller. This may damage the firmware.