Procedure for Enabling Open Firmware Password Protection
(written by CodeSamurai at SecureMac.com)

Enabling Open Firmware Password Protection
1) Boot into the Open Firmware. (Command + Option + O + F)

2) At the command prompt, type “password” (without the quotes, of course). You will be prompted to enter in the password you wish to use. Type your password, press the return key, retype your password again, and press return to verify that that the first password you typed is indeed the password you want. (Note: the password is stored in the “security-password” variable, but the contents of this variable is never shown via the “printenv” command.)

3) Type “setenv security-mode full” OR “setenv security-mode command” OR “setenv security-mode none”, depending on which level of security you wish.

4) Then type “reset-all” to restart the computer.

Disabling Password Protection

1) Boot into the Open Firmware. (Command + Option + O + F)

2) Type “setenv security-mode none” and press return.

3) Enter in the password at the password request prompt and press return.

4) Then type “reset-all” to restart the computer.

Force Removing Password Protection

1) Add or remove DIMMs to change the total amount of RAM in the computer.

2) Then, the PRAM must be reset 3 times. (Command + Option + P + R).