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How to Install Custom Firmware 3.90 M33-3 on a PSP Slim

The Sony PSP uses Sony firmware to run the device. There is, however, another type of firmware that you can run on the PSP: custom firmware. Using custom firmware is legal but will void your warranty. One of the most famous custom firmware groups, M33, is quick to implement the new features of Sony's firmware revisions on its own firmware. Installing revision 3.90, one of M33's more popular revision numbers, is quite simple.

Things You'll Need

Pandora battery
Magic memory stick

Instructions

- 1
  Turn your Sony PSP off and wait for the PSP to completely power down. Remove the battery and memory stick from their respective ports and place them aside.
- 2
  Insert your Magic memory stick first. This is what houses the M33 custom firmware. Insert your Pandora battery tool, and your PSP will automatically turn itself on. Your PSP is now in service mode.
- 3
  Press the "X" twice to start the custom firmware installation process and verify the installation. Wait as the custom firmware is installed.
- 4
  Press the "X" button again to shut off the PSP when the service program asks you to. Remove the Pandora battery and Magic memory stick, and reinsert your normal battery and memory stick.
- 5
  Turn on your Sony PSP, and you will now be running M33 3.90 custom firmware.

Sony PSP