NetBSD 1.5 (MRCOFFEE) #3: Wed Apr 18 05:56:48 MSD 2001
       toor@felix.sparc.spb.su:/opt/src/sys/arch/sparc/compile/MRCOFFEE
   total memory = 32396 KB
   avail memory = 28372 KB
   using 430 buffers containing 1720 KB of memory
   bootpath: 
   mainbus0 (root): SUNW,JDM1
   obio0 at mainbus0
   clock0 at obio0 slot 0 offset 0x200000:  (eeprom)
   timer0 at obio0 slot 0 offset 0xd00000data fault: pc=0xef0bcacc addr=0x0 sfsr=126<PERR=0,LVL=1,AT=1,FT=1,FAV,OW>
   panic: kernel fault
   halted
   
   Program terminated
   ok 
   
   The crash is in timerattach_obio.  As far as I can tell it corresponds
   to loading cpus[n] to a register during this test:
   
   		if ((cpi = cpus[n]) == NULL)


no surprise!  there are no attached cpus yet!  you will need to instrument
the autoconf.c:mainbus_attach() code after this comment:

/*
 * The rest of this routine is for OBP machines exclusively.
 */

to see why it fails to find the cpu.  i guess it isn't listed in the 
cpu.c:cpu_conf[] table...