Here is a collection of Adaptec PowerDomain PCI SCSI card firmware for
System 7/8/9 and OSX.

I had a lot of trouble finding firmware that would allow my 2940UW
(PC) to be reflashed to work with my PCI Mac... but I lucked out after
a long search and here is the fruit of my labor!

Stuffit archive includes firmware/drivers/utils for the following
cards:

2906
29160
29160N
2930
2940U2W
2940UW
2940W
39160
3940UW
SlimSCSI 1480
USBXchange

Compatibility
Architecture: 68k PPC (Carbonized)

Some flash tools require System 8 or newer to operate. I was able to
get many of the 2.x era tools to launch under System 7.6.1