eMac Open Firmware Password Reset

[gx240]

I just picked up an old eMac today that I'm trying to get it working. The problem is the open firmware password is set, and I have no idea what it is. If the open firmware password is set, it prevents you from doing anything without it including booting from a CD and zapping the PRAM. I changed the ram, removed the internal battery, and hit the PMU reset button expecting this to clear the password, but it didn't work. Removing the internal battery did reset the system clock to 1/1/1904, but didn't change anything else.

Also aside from the practical question about resetting the password, I'm suddenly left wondering where the system stores the open firmware password. If it isn't stored on the hard drive, and it doesn't depend on the internal battery, then how is it saved?

Just for clarification I have no idea who the original owner was or where it came from. So there is no chance of just finding the correct password.

[DeltaMac]

It's a 'firmware' password, so the access is stored in firmware, not in the hard drive at all, and (as you know) is not affected by the presence of a battery.

Changing the RAM is not enough. You have to change the memory capacity. If there's only one memory chip, add another. Of there's two chips remove one.
Reset the PRAM, continuing to hold the keys until you hear at least 2 more boot chimes.
That will reset that pesky password.

[ElDiabloConCaca]

The reset procedure as defined by Apple is the following:

1) Significantly change the amount of RAM in the system. If the computer has 1GB of RAM by two sticks of 512MB being installed, then removing one stick bringing the total amount of RAM in the system to 512MB would be adequate. Similarly, if the computer has one stick of RAM at 512MB, then adding another stick of RAM (128MB, 256MB, 512MB, etc.) would be adequate.
2) After performing the RAM upgrade/downgrade, turn on the computer and zap the PRAM by holding down the command-option-p-r keys while the computer turns on and keeping them held down until you hear the startup chime 3 times.

Plenty of information, as always, on Google:

http://lmgtfy.com/?q=bypass+open+firmware+password

I am not sure whether this simply bypasses the open-firmware password for that single boot and would require you to use the open-firmware utility to remove the password, or whether it removes the password. I'm sure that information is contained in the Google results, though.