Things You'll Need
Instructions
Press the "L1," "R1," "Select" and "Square" buttons simultaneously. You will be asked to enter the passcode for the kiosk. Enter the code to access the PS3 main menu.
Select the "Settings" option in the main menu. Select the "System Settings" option in the settings menu.
Select "Restore Factory Settings" in the next menu. Select "Yes" to confirm your choice and downgrade the PS3.