Instructions
Hold down the sole button on the Pandora blue LED battery. Release the button when the lights blink. The battery is now in Pandora mode. Turn off your Sony PSP and insert the Magic memory stick into the PSP card reader.
Insert the Pandora battery into the PSP and the PSP will turn on all by itself. Press the "X" button two times to install custom firmware on your PSP.
Press the "X" button again when prompted to shutdown the device. Remove the Pandora battery and Magic memory stick from the PSP. Reinsert your normal PSP battery and memory stick.
Turn your PSP back on and you will now be running custom firmware.