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Advice on finding BIOS for 486 Motherboard (GA-486US)

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First post, by dougvj

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I have a GA-486US (very interesting board with proprietary 32-bit bus) with a corrupted bios chip. I tried dumping the BIOS but I get nearly all FFs. I swapped the BIOS out for another board's with a different chipset and I got the board to POST but it doesn't properly configure the cache or see any memory above 640K, which is completely expected.

I cannot seem to find a copy of this BIOS anywhere online or even one with the same chipset (UM82C48). I have a MiniPRO and a compatible EEPROM so I can burn any image I want.

Any advice on where to look or what to do here? Picture of the board attached.

Reply 1 of 4, by cyclone3d

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Looks like MaxWar has or had one of these:
486 restoration project : need some advices and opinions!

I sent a PM requesting the BIOS since you are new and not able to PM yet.

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 2 of 4, by SteFam

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Hi I have a similar board here.At least the chipset is the same I will attach the bios, dont know if you still need it. BR stef

Reply 4 of 4, by Anonymous Coward

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This is the UMC 480 chipset, isn't it? Weren't those super common on 386 boards? Try the BIOS from the FX 3000.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

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