Instructions
Download the "PUP" and "Lv2diag.self" files onto your computer (see Resources).
Press the "Power" button on your PS3 Slim to turn it off.
Remove the power cable for the device from the wall outlet.
Plug your USB storage drive into a USB port on your computer. The folder for the USB storage drive will then appear on your computer.
Drag-and-drop the "PUP" and "Lv2diag.self" files into the USB storage drive folder.
Eject the storage drive from your computer, then plug the USB drive into the first USB port on your PS3 gaming system console and plug the power cable for the PS3 device into the wall.
Press the "Power" button to turn the device on and the PS3 system will power on in Factory/Service Mode.
Scroll through the Main Menu to the "Power OFF" option using the "Left/Right" and "Up/Down" arrow buttons on your game controller, then press the "X" button to turn the system off internally.
Remove the USB drive from the PS3, then press the "Power" button again and the downgrading process will automatically begin.