iMac starts up then shuts down.

msmcgillis

Registered
System ran fine on MacOS 8

Started to Install MacOS X things seemed to go ok. But, was taking hours to start.

Realized I had forgot to upgrade the Firmware before Installing MacOS X.

Shut down the computer. Now it will start up breifly then shutdown. Have attempted all the usual things like inserting CD booting with C key. Tried to get into firmware with command-option-o-f however nothing seems to stop the behavior of it shutting down. Shortly after I hear the cd spin up.

Any ideas how I can get it to respond to something?
 
Okay, if the CD's still stuck in the drive, find a paperclip (larger ones work better) and unbend one end, then stick it in the little hole to the right of the CD slot. This will activate the ejection method and eject the disc.

If that's not the problem, hold down Option when you start up. You should see a blue screen with some OS buttons, a round refresh arrow button, and a straight continue arrow button. Hopefully your 9 system shows up; if so, select it and continue.
 
Getting CD's in out using the method you identified works fine and have tried booting from a number of CD 8.x, 9.x, 10.x. However non change the behavior of it simply shutting down.

Removed all CD's and held the option key down. Again no change of it starting up then shutting down.

After powering it on you will get normal apple startup bong but shortly after that is when it shuts down. The monitor never shows anything. The start up button green light will lite up for a while then it goes off. The interesting thing is after it shuts off if you press the start up button again the green light will come on but nothing else. Once it is on the only way I have found to get the light off again is remove the power cord. Then you can repeat this sequance again once the power cord is pluged back in.
 
Unplug everything but the keyboard and mouse... Also, Eject ANY CDs!

Did you try to reset the PRAM by holding "Command-Option-P-R" on startup?

Did you try to boot into Safe Mode by holding "Shift" on startup?

What happens if you boot by holding "X" on startup?
 
With everything unpluged, and CD's ejected.

Command-Option-P-R on startup: No change in behavior

Shift on startup: No change in behavior

X on startup: No change in behavior

As best as I can tell my problem is that the flashrom is horribly confused at this stage. I'm guessing if their is some back door way to restore the flashrom this will all be fixed however so far I have found no information about possible ways to upgrade/restore the flashrom when the machine is not bootable.
 
If this were a Powermac, I would suggest you open it up and reset the PMU button located next to the battery, but since iMacs are hard to get into I'm not sure how you'd go about doing this. Someone else might know how to do this; at some point today, I'll attempt it on my iMac and tell you how well it went.
 
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