Hi,

I have taken a quick look at the web page you have linked and that site actually have specs for both the Cache-Memory controller(M1489) and the Goldstar Prime IO chip (GM82C803A/B).

From your description of the problem, to me, it seems that there is a problem in the way that the M1489 IC is initialized by that BIOS, when you tried to swap out the BIOS with another that one most likely initialized the M1489 IC correctly to use the cache, but that BIOS most likely came from motherboard that utilizes a different IO chip than the Goldstar Prime.

Looking at the spec documents available on the linked site, they seem to contain enough information about the M1489 to create somekind of a "Frankenbios" for the motherboard, which would let both the Cache and the FDC work properly, however that would require both experience with x86 assembly programming(without an OS) and access to the exact same type of motherboard that you have.

I would however recommend finding an updated BIOS for the motherboard, as it will be not an easy task, unless you already have experience in this field.

Decompressing that BIOS using amideco yields a section containing External Cache among the other BIOS options. It's most likely that the motherboard vendor set that option to be hidden.

Some AMISETUP versions can handle early WinBIOS. If yours is one of them, that is the easiest option: you run AMISETUP one-time which lets you set options in your CMOS that the BIOS has hidden, and the BIOS will obey them until the CMOS battery dies. This is in contrast to Award BIOS of that era, where it's easier to use MODBIN to un-hide options and flash a new BIOS.

Failing that, sometimes, the two "reset to defaults" options in the BIOS setup will have different choices for hidden settings, and one of them will set external cache to enabled even though it's a hidden setting.

Creating unique BIOS rom is beyond my experience, unfortunately. The only BIOS version I found is 101094, which Im using.
As for AMISETUP, is it meant to work with BIOS image files located on HDD, or does it modify the BIOS directly inside the socketed rom module?

Knoxville634 wrote on 2026-05-04, 21:15:

Creating unique BIOS rom is beyond my experience, unfortunately. The only BIOS version I found is 101094, which Im using.
As for AMISETUP, is it meant to work with BIOS image files located on HDD, or does it modify the BIOS directly inside the socketed rom module?

It doesn't modify the BIOS. Instead, it parses your BIOS ROM to figure out what hidden options it has (thus it must understand the exact AMI BIOS version to do this) and modifies the settings saved in your CMOS RAM. Despite supporting "hidden" options that the motherboard manufacturer thinks shouldn't be tampered with, the AMIBIOS will still obey those settings in the CMOS so long as the checksum is correct (the other part AMISETUP handles).

I've used AMISETUP with uncompressed (1994ish) WinBIOS machines. What I'm not sure of is if yours is slightly too new. There are also multiple AMISETUP versions, so you might have to try more than one.