Q: Help: Can't Boot into Open Firmware

I can no longer get my iMac to boot into open firmware. When I restart with the cmd-opt-o-f keys held down it will not go into open firmware. It just boots normally into Leopard. What could be wrong? I am currently experiencing major system slowness so was going to try the reset-nvram, set-defaults combo just for kicks before I backup and attempt a clean install.

iMac Core 2 Duo 2.16 GHz, Mac OS X (10.5.4), 2GB RAM

Posted on Sep 9, 2008 9:51 PM

I have this question too

Q: Help: Can't Boot into Open Firmware

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by Kenichi Watanabe,

Kenichi Watanabe Sep 9, 2008 10:39 PM in response to Larry Jorgenson
Level 8 (38,441 points)

Mac OS X

Sep 9, 2008 10:39 PM in response to Larry Jorgenson

Are you using an Apple keyboard? Wireless keyboards made by Apple should work with your iMac, but is it wireless?
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by Kappy,

Kappy Sep 10, 2008 12:00 AM in response to Larry Jorgenson
Level 10 (270,411 points)

Desktops

Sep 10, 2008 12:00 AM in response to Larry Jorgenson

There is no Open Firmware on Intel Macs. COMMAND-OPTION-O-F does not work. Intel Macs use EFI not Open Firmware. If you need to access single-user mode then boot using COMMAND-S.
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by Larry Jorgenson,

Larry Jorgenson Sep 10, 2008 6:36 AM in response to Kappy
Level 1 (30 points)

Sep 10, 2008 6:36 AM in response to Kappy

Oops. My bad.

http://support.apple.com/kb/HT1533

So, does the old "zap the PRAM" which is now listed in the chart as Reset NVRAM actually do the same as the older open firmware reset-nvram command? What about set-defaults? Can you enter these commands in single user mode? I never tried that.
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Q: Help: Can't Boot into Open Firmware

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by Kenichi Watanabe,

by Kappy,

by Larry Jorgenson,

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