feipoa wrote on 2024-02-01, 12:54:
I may remember incorrectly, but I sorta recall motherboard versions which were sold with a UV EPROM chip contained a BIOS revision which did not try to update ESCD information. Did you see Updating ESCD... with your BIOS before you flashed it? Or did this only happen after you flashed it?
I'm pretty sure you need an EEPROM to update ESCD information. I don't think the UV EPROMs normally contain a EEPROM section to maintain ESCD.
For what it's worth, the original version of this board I used in the 90s had working Updating ESCD...Success only when a hardware change was made. As that was sold within an OEM system with a "Designed for Windows 95" sticker, I suspect the Windows Logo requirements might have included a working ESCD while those sold by the piece or to system builders may have used the cheaper part. The Updating ESCD also happened when encountering the "disappearing PS/2 mouse" problem mentioned in your manual, so the message was always bad news.
A few years back, I got one of these boards from eBay that came with a UV EPROM. It shipped with a BIOS named "UUD960326S." (notice the dot versus the normal version without). It printed "Updating ESCD..." at every boot but did not hang.
When I tried flashing a "modern" Flash chip (39SF010) it switched to hanging at Updating ESCD. I believe it has something to do with the original EEPROM being byte-programmable while the Flash chip is page oriented.
When I switched to a "period correct" EEPROM (29PHEE010) it went to "Updating ESCD...Success" only on hardware changes.
Later versions of Award BIOS, but not this old 4.50PG one, seem to have a list of allowed EEPROM/Flash IDs embedded in them, possibly to avoid the hang when it tries to program an incompatible chip.