iMac Firmware Problem?

A

A Robinson

Registered
Help! While trying to upgrade firmware on a 333 iMac prior to upgrading OS8.5 to OS9, I have created a situation in which the machine will only start in a command-line mode - I suspect that both embedded firmware copies are corrupt. Does anyone know whether it is possible to replace/update the firmware from a CD at this point? Can anything be done from the command-line interface?

Any help would be appreciated - it's not terribly useful in this state...

Thanks
 
Did your iMac begin going to this command prompt immediately after starting the firmware update? No other reboot since then? The only command line you would be seeing is the Open Firmware command prompt.
try this: (no quotes, just the command as you see it)
Type 'reset-nvram', then press enter
you should see 'ok"
then type 'reset-all', then press enter, your system should reboot, and go into OS 8.5 again, If the Open firmware prompt comes up again, then type mac-boot, and then enter. That should do it.
If that's a nogo, then try booting up to the OS 9 install CD, then set the startup disk for the hard drive, and reboot!!
 
Thanks - worked perfectly.

In twelve years of Mac experience (including a lot of Power Macs), I've never encountered the Open Firmware prompt...

Is there any good (non-programmer) source of documentation on this subject?

Thanks again for your speedy reply.

Art
 
If you do a search at the Apple web site, you'll a variety of articles about Open Firmware, which are a part of the Apple New World ROMs (All iMacs, B&W G3s, and all later Macs, I don't think the Beige G3 has New World ROMs, but I could be wrong) There is some software you can dowload that lets you configure Open Firmware for a password to disallow booting to CDs, and a few other security options that this provides. I see some posters here that have researched the setup and use of commands in open firmware, but usually just knowing how to reset the NVRAM and PRAM (the same in my post above), and how to exit the prompt to get back into the normal Mac OS, that's all that interests me. You may have other possibilities. :)
 
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