If you own a PSP system with a custom firmware installed on it, you may wish to reinstall the original PSP operating system onto your device. All custom firmwares that can be installed on the PSP system come with a Recovery Menu that will allow you to access a slew of recovery options for your device. With the proper eboot file on your PSP system, you can even use the Recovery Menu to restore your device to its default operating system.
Insert the USB memory stick into the memory stick slot on the side of the PSP system. Connect the PSP to a computer via the USB connection cable that came with the PSP system. Turn on the PSP system and navigate to the "Settings" section of the Cross Media Bar. Scroll down to the "USB Connection" option and press the "X" button to place the PSP into USB mode.
Open the computer's Web browser and navigate to the PSP update page (see Resources). Download the latest PSP eboot.pbp file onto the computer. Double-click the PSP icon on the computer to open the PSP's root directory. Open the folder titled "Game," create a new folder and title it "Recovery." Place the PSP eboot.pbp file into the "Recovery" folder.
Right-click on the PSP icon and select the "Eject" option to eject the PSP from the computer. Disconnect the USB cable from the PSP system and press the "O" button to take the PSP out of USB mode. Slide the PSP's power switch up and hold it there for 10 seconds. After 10 seconds, release the switch button and leave the system off for at least 30 seconds. This is called a hard reset.
Hold the "Right Trigger" button and flick the power switch up to turn on the PSP system after the hard reset has been completed. The PSP should now boot to the Recovery Menu. Scroll down to the "Run program at /PSP/GAME/RECOVERY/EBOOT.PBP" option and press the "X" button. The PSP should now begin to reinstall its original operating system via the eboot.pbp file you downloaded in Step 2.
Allow several minutes for the installation to finish. Once the installation finishes, the PSP system will reset and boot up with the original operating system installed.