AsRock BIOS Mod

Hi,

i'm trying to mod the bios of an Asrock K7S41GX board.
This board use AMIBIOS CORE 7 , bios link :

asrock.com/MB/download.asp?Model=K7S41GX&o=BIOS

The version i'm workign on is the latest , 2.80 .

The tool used to edit the bios is AMIBCP75.

All seems to work well , i can edit modules , insert and replace , but the problem is that the bios file produced by AMIBCP is different from asrock original one . I'll explain : if i extract a module , for example the DMI Data , module #6 , then reaplce this module with the one extracted (no modifications made) and save the rom , what i obtain is a bios file identical to the original asrock file , except for the first 4 bytes that are set to 0xFF.

I don't know if those 4 bytes at the start of the bios file are a CRC or checksum , i tryed with many CRC algorithms but none seems to give correct result , so i would like to know what those 4 bytes are . Since i don't have another board and since AMIBIOS.ROM method for recovery don't work on asrock motherboards i want to be sure that flashing the bios with those bytes changed won't lead to a non-functional board.

Thanks.
Nico.


Move to BIOS Edition forum.
maco