Chipset initial registers: EB9F-EBB8

30 2A 
31 6F 
32 E5 
33 00 
34 8D 
35 97 
36 90 
37 FF 
38 86  <- Change this for C8000 ROMCS#, (PCMCIA area also)
39 00 
3A 00 
84 00 
3B 00

D000 would be good for the XTIDE Bios, C800 not so good,
as it is also used for PCMCIA

Subfunction at F000:8706 does the Shadow ram stuff for option roms

8716: Shadow D0000 enabled, mob bh 00001111b
Change to 00000000b

Place XTIDE Bios to 10000h (D0000)

38717: B7 0F -> 0E Set "32h Shadow D0000-D3FFF" Disabled
38754: C3 00 -> 10 Set "37h D0000 ROMCS#"
38972: B3 F0 -> F1 Set "32h Shadow D0000-D3FFF" Enabled

For C800: Place XTIDE Bios to 8000h

3EBB0: 86 -> 9E Enable C800,CC00 ROMCS#

3873A : B7 4C -> B7 40 C800,CC00 Shadow disable
3875A : B3 E7 -> B3 FF C800,CC00 to ROMCS#

38981: B3 B3 -> B3 BF Shadow C800,CC00 Enable