snad tohle pomuze
1. Shut down the power supply for at least 15 seconds.
2 Turn on the power supply and then press and hold the power button and reset simultaneously for 10 seconds.

The board should turn off and on a few times and then show the recovery screen copying the backup BIOS for the main BIOS.
I also have a b75m-d3h that had the same issue and this procedure was the only thing that worked