Deksor wrote on 2021-01-13, 16:22:
Which motherboard do you use ?
most 486 motherboard use 64KB ROMs which are very often compatible with 27C512 chips, but some socket 3 boards use 128KB chips of another kind (same kind as later pentium boards)
There are a couple of motherboards, I don´t have access to look at them right now but one I remember the name of is MS4144. It´s a PCI 486 board, and it seems the BIOS file is 128kb.
TheMobRules wrote on 2021-01-13, 16:28:
Yes, 27C512 is the most common one, in that case you can use W27C512 as a replacement which is an EEPROM and doesn't require UV to be erased. Several late 486 boards already come with EEPROMs.
I tried searching for this part number on mouser but it was listed as discontinued. Is there another variant that mouser sells that I can use? Should I just order 128kb variants and use that for BIOS files that are 64kb or should I use the "correct" size for the motherboard?
Thanks for all help in this matter, I´m completely new to ROM chips and burning them. I did recently manage to burn a XTIDE ROM and use it in an old 286 but that is all the experience I have in these matters 😀