Things You'll Need
Instructions
Turn off your PSP Slim and remove its battery and memory stick. Place these to the side.
Insert the Magic memory stick into the PSP Slim's memory stick reader.
Insert the Pandora battery into the PSP Slim's battery compartment. The PSP Slim will turn on automatically. If it does not, turn it on manually.
Press the "X" button one time to install custom firmware onto the PSP Slim. Press the "X" button once more to power off the PSP Slim.
Reinsert the normal battery into the PSP Slim and power it back on. You are now running custom firmware on the PSP Slim.