Well, you've gotten further than *I* ever had... 

I'm about ready to commit some slight changes to trap.c that
will make things a bit more chatty (printouts) about why one is
dying. That may help you find out why you're getting an instruction
fault- although if you aren't seeing any printout at all
in the current code you took an instruction fault in kernel mode-
very bad.

What h/w do you have again?