Arducopter error config failed to update IO firmware

Like the title says. Flashed holybro X6 with the latest FW and got this error message instantly.
Tried different versions, tried to manually set the brd_type, nothing made a difference.

Don’t ever do that. Try using QGC and choose Ardupilot Stable version.

I only did it using qgc. I even tried mission planner but result is the same

When using MP did you download the Stable .apj file from the repository and use “load custom firmware” to flash it?

I tried both, choosing it from the list and downloading stable and loading custom firmware.

There was a change merged into Master recently for the 6X, try that. Download the .apj from the “Latest” repository. Unless you tried that already.

Tried that, but still the same issue.

I tried even the latest DEV version, but still the same issue. Can it be something regarding the baseplate?

I have had issues with failed updates on the 6X, try holding down the safety switch when powering on to see if that makes a difference

I do not have the safety button anywhere. The baseboard has been designed by us. I ordered a regular baseboard to see if it makes any difference.