General SPARC hardware question, no relation at all to NetBSD...

Just wondering if anyone had ever seen a ss5 switch the disk ids of the
drive for no good reason. I was having problems booting the machine because
it was set to boot only from 'disk' (scsi id 3), and somehow the disk was
running as id 2 (before this it had been on 3). So I switched it to boot
from 'disk2', and, after a couple test boots, you guessed it, the disk went
back to id 3 (this was of course AFTER I put it back in my closet and
disconnected the serial line). Anyway, I set it to boot from 'disk disk2'
in the PROM and everything is fine now. I did not move the disk, remove or
add jumpers, or do any other stupid thing like that.

Just wondering if anyone had seen this before, I'm mildly worried that the
PROM, SCSI bus, or disk may be dying.

Thanks,
  Jack