Instructions
Select the "Settings" heading from the PSP menu. Select "System Update" from the "Settings" subheading.
Select "Update via Internet" from the PSP's update settings. The PSP searches for a Sony firmware update.
Select the "Download" option. The new firmware is downloaded directly onto the PSP's memory card.
Select "Accept" when asked to agree to Sony's terms of the software agreement. Press the "X" button once more to install the Sony firmware.
Select the "Settings" option on the PSP menu again after the downgrade to Sony official firmware.
Select "System Settings" and "System "Information." Verify that the "Current Firmware" is the current Sony firmware you installed.