I am using this board in 386 mode - I had mixed results with the different MR-BIOS available for this chipset, with "V037B302/UMC_302" working best. There are different versions of the BIOS for UM82C481 rev 0 vs rev A/B, my board has rev B (UM82C481BF). I have not tried this BIOS with the board in 486 mode. Sticker from Geekenspiel.

V037B302 UMC_302 386 WriteBack, Rev A,B *ONLY* (Not REV-0 !)

Can I use a W27E512-70 chip to flash the BIOS on this board?

muon wrote on 2025-07-06, 16:19:

Can I use a W27E512-70 chip to flash the BIOS on this board?

I got it to POST using the MR BIOS "V037B302/UMC_302" ROM in furan's post (Thank you furan) written with my trusty MINIPRO TL866CS programmer to a WINBOND W27C512-45Z EEPROM and yes it saw my 486DX2-66 CPU as well as my PNY QuickChip AM5x86 133MHz CPU upgrade set on Option 2 4X Pass Through third option in manual as it was all I could get working.

Just to give an update if any one is in the same situation as me - I got this board with the 386 socket unpopulated.
I installed a socket from a broken board and to my surprise the board works just fine with 386 cpus now.
The only thing that needs to be also addressed, depending on the 386 cpu you want to use, is the crystal oscillator which and easy fix.