Is it possible to diff the contents of 0xc0000-0x0d0000 under both the factory and linux bios? I think you may have said that you have to use different copy of the video bios for linuxbios?
Ok, first result of factory bios:
Via Epia-ML Bios Version 1.1.16 included VGA-Bios called Mclecomb.rom
get file with
dd if=/dev/mem of=vga1.rom bs=1 count=65536 skip=786432
later I have done a dd on vga1.rom with count 60146, because the extracted vga_bios from origbios.bin has a size of 60146
cmp -cl origvga.rom vga2.rom
There are two different offsets. Offset 1A is A5, original Offset 1A is A6 Offset 5D is 01, original Offset 5D is 00
Unfortanetly I can not write the differences from Linuxbios, because, there are to much :D
LinuxBios included VGA-Bios Mvpsd_15.rom from Epia-M Bios Version 1.1.13
if you want, you can have a log file ;) It seems, nearly the half code is overwritten.