Does it behave with a HDD between 600MB and 2GB?? Or none to test with? You could be on the right track hunting an update, when first EIDE cards were out IDE HDD had barely pushed past the 540 barrier, 850 was the monstrous beast, 1GB was announced for intro in a few months and 2GB had to be all the disk you'd ever conceivably want.

Edit: I think I remember Promise tended to be dicks about firmware upgrades, even if it fixed a bug or an absent advertised feature i.e. "Yes we have it, that will be $$$ please." so I guess you'll be looking for a dump.

It worked with my 4.3GB HDD without issues in a previous system (a 386 before I swapped the board that has VLB (J-Mark OPTI495DX 3/486WB) and a VLB dual IDE + dual FDD card for the floppy drives and the 8GB CF card).

Ah, I see, so does it make it past there deturboed or L2 or L1 disabled? Only needs to configure once right?

Only needs to be configured once and it worked with my 386 either with the normal speed (386DX-33) or slow speed (386SX-16)

Does it work with any drive in the 286? Could the card ROM be 386 only?

It doesn't work with any drive I throw in there, especially a 2GB Quantum Fireball. The BIOS works in a 386 machine and not a 286.

Edit: if I set the drive to Master, it'll say no drive was found and this is with a 2 drive IDE cable (I had a couple of single IDE cables, but the one is in use in my 486 and the other is too short to reach the drive (and it's either misplaced somewhere or it's currently in my 386 machine).

With the drive in either CS, slave, or single mode, it'll show the setting up the 1st drive message for a second and disappear without it showing the drives being listed. I disabled the secondary IDE and might re-enable that to see if that clears the issue or if the BIOS ROM is the issue with the system.