Can't help as such, but I did find a very similar card:
https://computer-retro.de/Bilder/Multi-IO/LCS … C-Chip-1993.jpg

Nearly the same PDC20230 (C rather than your B), UM82C863F and UM82C865F, and it doesn't look like it needs a separate BIOS chip, or any of the unpopulated pads on your board. Also it doesn't look like any chips where ever fitted to the empty pads on your board (no signs of solder). I'd guess that the PCB could be used for different versions, just fitted with different parts.

Worth trying different jumper settings for IRQs and BIOS addresses and disabling everything except for the HDD, in case there's a conflict with anything else in the machine?

I have also QD6500A VLB card and one unpopulated logic IC (74138) must be inserted to run external bios.
I measured connections between ISA connector and 74138, and probably in this card Gal16V8 is required so almost impossible job to recerate it

I dont think this will work without the 16V8. And the 16V8 needs to be programmed. Look at the traces running from the BIOS jumpers, they connect to the 16V8. It seems to be required to select the adress.

Your card was a bad choice for adding the socket. I already did this successfully wit another VLB controller. I added a 74LSxx in addition to the ROM socket...

It looks like there's a deliberate 0 ohm link across pins 11 & 19 of the 16V8, so it may not have been fitted originally, unless someone's made some strange mods.

mt777 do you have a photo of the back of the card to help see where the traces go?