Things You'll Need
Instructions
Keep your console powered off. Remove the PSP battery and memory stick from your PSP. Locate your magic memorystick and Pandora battery. With your PSP still off, insert the magic memorystick.
Insert the Pandora battery. The insertion of the battery into the PSP will automatically turn it on and present you with the Pandora menu, shown here.
Press X to start the downgrading process. Press X once more to accept all risks involved in using the Pandora battery. Once the process completes, press X to turn off your PSP. Immediately remove the Pandora battery and plug your PSP into the A/C charger and turn it back on.
To verify that everything went smoothly, go to your PSP system settings and view the System Information. The system software should read "Version 1.50." If it does not, restart from step 1---it may take a few tries to be successful. You are now ready to install custom firmware into your PSP.