cool mac firmware reset, (help find lost firewire)

[sonariste]

I copied this post from the DUC. Never seen this reset before, It seems to really help with apple g4 towers that lose usb and firewire compatibillity.
(Happens about 3 times a year to me on my G4 dual 450)

Hey MrPT,
One thing you might wanna try is resetting Open Firmware - this tends to help alot with FW and USB connection issues.
Restart the computer, and at the boot chime, press and hold Command (Apple Key) + Option + O (the letter, not a zero) + F. When you see a kind of grey screen with the words "Welcome to Open Firmware" in the upper left corner, release the keys.
At the prompt, type in the following - lowercase with no spaces, and no quotes: "reset-all" then hit Return.
The machne will automatically reboot and then test it from there.
You could also try resetting the CUDA chip on the Logic Board if your comfortable getting inside the machine - Power down, make sure your grounded (you can even just touch one of the metal PCI slots on the back), unplug everything (power cable, display, etc) and pull down the side panel - on the Logic Board, look for the Battery (looks like a scaled down version of a normal battery, sometimes green or purple in color), and right next to it, you'll find a small, silver button (some machines, the color will differ) - press and hold (carefully) for about 10 seconds and release, then reconnect everything and power the machine back up and test.
** Depending on your machine, the reset button might be on the side of your Logic Board with the words "PMU reset" or "reset PMU" written next to it - this is the same button you'll want to press.**
You can also try running the Apple Hardware Test and see if that picks up anything - I have seen it miss some major problems before, so you may have to loop it overnight, but def give it a run.
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This was posted by an ex- tech support guy from apple.

[ladewd]

Yep, I saw that and copied it for future reference. Good thing to let everyone know.

[touched1]

Uhhhhh yeaaahahhh.....

I kinda sorta fix macs for a living, and was specifically told by Apple not to hold the cuda chip for more then a second or you could crash the pmu.

Other variations on this procedure are to hit the power button after unplugging which will cause the fan to spin 1/4 turn on PCI or AGP G4's, I forget which, then to remove the battery for 10 min before resetting the cuda.

The cuda is always a small black round button encased in a silver square housing.

Other than that the instructions all seemed good, especially unplugging before doing this.