iMac 27" 2019 - Apple board replacement



I have ordered a replacement board on ebay for an iMac 27" 2019 and got apparently an Apple replacement board with no SN.
I went to flash the original serial using the blank board serializer and all that worked fine.
However once I started updating the OS I was prompted by a firmware update failed when going from Mojave to Sonoma.

After some investigation I have realized the board identifier model is AAPJ1381,1 which I guess is what is triggering the no-pass on the firmware update.
I'd like to try a clean Bios dump if it exists or use my previous board Bios dump and clean it up, however I am not sure how to do that.

Can someone please help me with it?