I sent a request for help to AsRock support team, but you have to wait long for an answer. This is their first response:
I assume it did work correct with the original BIOS version, but it is impossible to flash back to the original version.
Can you give me more info?
Kind regards/ mit freundlichen Grüßen,
ASRock Europe B.V.
6604 LV Wijchen
my question was - what exactly you need to know ?
and now again waiting for response