Try the drivers here: https://68kmla.org/forums/index.php?/topic/54 … #comment-582045

Apple's DOS card used the C&T 82C450, so the drivers may work with your card. The disk set includes drivers for Windows, OS/2, and DOS applications.

So I've tried the above, and...

I've also found the software for another card based on this chipset, OCTEK EVGA - https://archive.org/details/ChipsTechnologies … rAndUtilityDisk
...but no luck, either - the chipset obviously does support emulation modes, but the STB BIOS doesn't cooperate.

All my hope is now in the utilities from STB, so I'm still looking!

This card would fit perfectly in some XT, if I only could enable its CGA emulation mode...

I found a listing from STB's FTP site in 1995 and 640UTIL.ZIP wasn't there .

http://files.mpoli.fi/unpacked/hardware/displ … .zip/stbftp.txt

Maybe this would help .

https://studfile.net/preview/894288/

1----------105F01-----------------------------
2INT 10 - Set Emulation Mode               (Chips and Technologies Super VGA)
3        AX = 5F01h
4        BL = Operation Mode
5               0-1 Reserved
6                 2 Enable CGA Emulation
7                 3 Enable MDA Emulation
8                 4 Enable Hercules Emulation
9                 5 Enable EGA Emulation
10                 6 Enable VGA Emulation
11Return: AL = 5Fh  If function supported
12        AH = Return Status
13               1 If Function Succesfull, 0 else

And a datasheet for the 82C452 (conceivably similar) . . If you can bypass the BIOS and set the right value in the right register, it might work (beyond my skill set).

EDIT : Also the Epson Equity 386SX Plus used a 82C452 . The Epson FTP Europe site is archived, but there is no Index and it is 226GB in size .
https://archive.org/details/2015.02.download. … pson-europe.com

The problem is that the INT 10h "Set Emulation Mode" function obviously isn't implemented in the STB BIOS - the SetVGA utility tries to call that function and fails.

I've got the datasheet for 82C451, so indeed I can write my own utility, but that's not a priority - I have some other 8-bit VGA card as well...