Okay, you are calling on me to join this thread and I’m happy to share my views on this Biostar socket 5 BIOS issue.
Yes, I recently joined this fine community and find you all very knowledgeable in a wide range of retro PC subjects. I hope I can contribute with my specific knowledge of the Award v4.50/v4.51 BIOSes.
I started patching BIOSes for better CPU support in 1997 when my 486 rig wouldn’t run an Am5x86-133, and I’ve mainly patched socket 3 and socket 7 Award BIOSes since.
I’ve only once tried to patch a socket 5 Award BIOS. This was for the Edom MP039 board, that runs on the same OPTi Python (546/822) chipset as the Biostar from the OP.
At the time, I found that patching this BIOS for proper AMD K6 support was not feasible. No MMX or AMD support, not even for the AMD K5 and therefore a lot of support functions for non-Intel CPUs where missing.
However, I find jakethompson1’s idea very appealing. Just remove any offending code for the K6-2, like the Write to MSR 2, so the AMD can at least boot. We have good utilities now that can fix any AMD CPU registers programming from DOS or Windows and optimize performance.
I will start analyzing the 08/31/94-OPTI-546-822-2A5UMB01-00 BIOS for the 1500PCT series and report back what I find.
@jheronimus, can you confirm this is the BIOS you are using? And please let us know at what POST code the BIOS hangs when using the K6-2. This will greatly help in finding the culprit. 😉