Mac OS X 10.4.4 Special Report: Inexplicably booting into Open Firmware mode

CNET staff

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CNET staff

Sept. 2, 2009 9:09 a.m. PT

2 min read

Some users are finding their Macs inexplicably booting into Open Firmware mode after the update to Mac OS X 10.4.4.

If you are accidentally booted into Open Firmware, you will see a message like:

"To continue booting, type 'mac-boot' and press return"

If you receive the message you should type:

reset-nvram

at the prompt, then press return. Next, type:

set-defaults

and press return.

Finally, type

reset-all

and press return. Your system will restart and should boot normally.

If not, try resetting your PRAM by shutting down your Mac, then starting it up again while holding down the command, option, P and R keys until you hear the startup chime twice, then releasing those keys.

MacFixIt reader Eliezer Kanal reports that in some cases, the issue may not be related to the incremental system update at all, but rather an errant connected device.

Eliezer writes:

"I had this issue myself, and I found that the problem was actually incredibly simple. I'm using an old dual G4 500 attached to an Apple Studio Display, and it appears that the power button on the Apple Studio Display would occasionally get stuck when I pressed it to turn the machine on. It seems that if the power button stays pressed for five or ten seconds or so, the machine boots into open firmware mode. On my machine, you can tell if this is the problem by observing the power button on the display during startup - it should brighten when pushed and immediately fade out a bit. If it stays lit, then your button is likely stuck, and you may go into open firmware mode."

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