Is this the stock CD-ROM of the Ultra 5? If not, and it's been replaced with a CD-ROM for a PC, then the block sizes are different and the CD-ROM shouldn't boot (sometimes it does, but normally no). I believe Plextor is one of the few CD/CDRW drive manufacturers that make aftermarket drives that are able to switch to the block size to boot solaris. I believe the block size to boot is 2048 instead of the standard PC block size of 512. Don't quote me on that, though.
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