To set the security mode:
ok setenv security-mode full
ok setenv security-mode none
Disconnect power, open up the chassis, and locate the EEPROM on the motherboard. It is a rectangular black plastic block (IC = integrated circuit) about 2" long, 3/4" wide, 1/2" high, possibly with a yellow sticker on it. In some machines, the IC is placed in an additional plastic socket, which ensures that the IC is not placed in reverse. Remove the IC from the motherboard.
Now place the IC back into its socket backwards, i.e. rotate it 180 degrees. Connect power but do not turn on the machine. In some cases the EEPROM is damaged if the machine is turned on, in other cases, it has no negative effect. Leave power connected for about 10 seconds. This flashes the EEPROM.
Disconnect power, remove the EEPROM, and place it back into the socket the correct way, i.e. rotate back 180 degrees. Close the chassis, connected power, and turn on the machine.
At this point, the values in the EEPROM should be reset to their defaults, including no security mode and no password.
If the machine previously booted from a non-default location, this location must be set again.
To set MAC address (AA:BB:CC:DD:EE:FF) and HostID (GG:HH:II), perform the following steps:
Sun typically uses 08:00:20 for the first three hex values:
ok 8 0 20 DD EE FF GGHHII mkpl
ok 8 0 20 DD EE FF DDEEFF mkpl
ok f idprom@ 1 xor f mkp
To check the value of the IDPROM, type: