firmware upgrade problem

[Jonathan Park]

Hi,
I"m trying to upgrade my firmware, as advised in the manual, before
upgrading from 9 to osX
Currently I have "boot rom 4.1.3f2", and was attemping to upgrade to
4.2.8.  I attempted to upgrade and was unsuccesful.

 here's the problem I ran into:
After pressing and holding down the proper button on restart and following
the instructions I got a line command screen.

"Welcome to open firmware, the system time and date, ... etc.
to continue booting type "mac boot"  to shut down....etc.

After typing in the "mac boot" , the computer booted up, but I received a
message "your power mac was not updated, review instructions and begin
again."  Which of course I did and I got the same message again, and again.
etc.

Any ideas?

I have a :
G4  466mghz  Digital Audio
machine id 406 (if this is pertinent)

Thanks,
John Park