Also, what kind of CD ROM drive to you have?  I've had this 
problem with older DEC drives, such as the RRD40.  They give 
this spastic response to 'show dev' at the boot console, but then go ahead 
and work just fine if you say "boot dka0" (be sure you know which ID they 
are!).  It's also specifically on a '90 that I've seen this behavior.

Doug Meade