You're thinking of the PALcode and yes, the PC164:s do have both the UNIX and VMS specific ones in firmware. It should be ready to just rock & roll.
AlphaBIOS is an SRM replacement intended to facilitate booting Windows NT I believe. I never really looked at it.
Afterthoughts:
Since your machine is running Windows NT, you'll likely need to flash it with the SRM ROM, but this I've never done so I don't know how that works. Presumably you put the right ROM on a floppy and tell AlphaBOIS to update from it. Manuals for the machines still exist on the HP ftps... somewhere. (time passes) I dug out the manuals I've saved and put them here for you:
http://duck.at.shangtai.net/files/Alpha/
. Looking at it the "pc164srmcons" PDF actually tells you how to switch, so there you go
The AlphaBIOS ROMs are named "
xx
164nt.rom" where
xx
is pc, sx or lx for the approriate system, while the SRM ROMs files are called "
xx
164srm.rom". Alas I only kept a couple of ROM files for SRM for my AlphaPC (no suffix) so I can't help you with that. They were distributed in ZIP files, the AlphaBIOS ones I found here are named "AB566-F.ZIP" (AlphaBIOS firmware for the SX) and "AB5561-E.ZIP" (AlphaBIOS firmware for LX)... I don't seem to have kept the zip files for SRM. (Hm, AB probably stands for AlphaBIOS and 566 sounds like the version, 5.66)
With SRM the process is very simple, just put a fat-formatted floppy in the drive with the files fwupdate.exe and the ROM file and run "fwupdate" from the >>> prompt. There's also a failsafe if you manage to screw things up that you can access by shorting a jumper on the motherboard, it will then flash the firmware off a floppy when powered on (well, IIRC, I've done it
once
) and then you have to remove the jumper and reboot.
Gotta run, hope it works out. The AlphaPC is a fun little machine with surprising capability (I'm continually surprised how responsive mine is under load).