From ok prompt type banner. If the
ethernet address is made up of mainly
ff:ff:ff:f:ff kind of address (basically more
f's than you would expect) , then the
battery in the nvram has failed
You could try set-defaults at the okay
prompt and try again. Watch it though, cos
it will change your boot paths.
It might be but is less likely....
You could also make sure that the device
you are trying to boot from is visible by
power cycling the box, and when it says
Initializing memory /
hitting STOP-A or break (normally F5 on
vt100) and doing a probe-scsi at the ok
prompt.
If the disk appears, then you should make
sure that it is set up properly in the
devalias list.
Type from ok prompt
ok devalias.
Make sure the boot path is specified.
If not then that's a whole other procedure.
Might help