Deksor wrote on 2021-04-21, 17:22:

Thanks for the BIOS upload ! Straight away when opening the ROM in a hex editor I can read "MB-1333PMA-CH, MB-1333PMB-CH, MB-133 […]
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Thanks for the BIOS upload ! Straight away when opening the ROM in a hex editor I can read "MB-1333PMA-CH, MB-1333PMB-CH, MB-1333PMD-CH, MB-1333PME-CH
MB-1340PMA-CH, MB-1340PMB-CH, MB-1340PMD-CH, MB-1340PME-CH"

The POST string is 30-0201-D61223-00101111-050591-OPWB, 1223 being Biostar's manufacturer code, this suggests this BIOS was originally made for one of these boards http://www.win3x.org/uh19/motherboard/show/1068 http://www.win3x.org/uh19/motherboard/show/1069 http://www.win3x.org/uh19/motherboard/show/1067 (and actually the POST string can be found in the second one I listed)

Doing a checksum on these two matching bioses shows me that they're different somewhere. I don't know what's the difference though (bit rot ? different version ? bad dump ?)

loading both in hxd and doing a compare... the first diff in the unknown is 000-1-0000-00-00-0000-00-00-00-8 vs 000-1-0000-00-00-0000-00-00-00-9 in the already listed, so slightly different previous version? only 13 bytes different.

The Biostar BIOS reports 256 KB of cache that the board doesn´t have and 384 KB of Shadow RAM.
There might be just a tiny difference between the two when detecting and categorizing memory. One of the Biostar mainboards even has an Opti chipset, but all of the Biostar boards do have L2 cache.
The BIOS my board came with also has the golden sticker with the fragmented "b" logo. I should have paid more attention to this detail.

So I think it´s definitely Biostar.