Just an idea (and I must admit I'm not too familiar with the Blizz PPC cards), does you board have SCSI? I know some Apollo cards will search forever (black screen) for devices, unless SCSI is disabled.
Another thought, IMHO there's nothing wrong with trying 3.1 ROMs. E.g., I have an '030 card that only likes 3.0 ROMs... so as I see it, it's a cheap/easy thing to try.
