[recondas]

Since you've gotten into the PROM you might try booting IRIX in single user mode.

If the system boots, you can test the viability of your IR graphics hardware using irsaudit.

If you aren't familiar with irsaudit, the basic use is described here:
https://wiki.preterhuman.net/InfiniteRea...h_irsaudit <I have no idea whose web site that is, which is interesting since I wrote that guide (-; >