Clean install or downgrade firmware with Chronoswitch Downgrader

Download Chronoswitch Downgrader and Official Firmware update

Download Chronoswitch Downgrader:

Chronoswitch Downgrader (Github)

Download the 6.61 Firmware:

PSP 1000, 2000, 3000, E1000 (Street)

6.61 Official Firmware (Archive.org)

PSP GO

6.61 Official Firmware for PSP GO (Archive.org)

TIP

If you wish to downgrade to another firmware, you can download them here: Darthsternie firmware archive

WARNING

Do not downgrade below 6.20 Official Firmware

Rename Firmware Update file

Extract the firmware from the zip file and rename it to EBOOT.PBP

661.PBP > EBOOT.PBP

Transfer files to the console

INFO

For the purpose of this guide, we will assume that your PSP / Memory Stick has been assigned the drive letter X: by Windows.

Transfer the Firmware Update file to your PSP and place it inside the UPDATE folder. (If the folder doesn't exist, create it).

The Firmware Update file must be placed here:
X:/PSP/GAME/UPDATE/EBOOT.PBP

Transfer the ChronoSwitch folder to your PSP and place it inside the GAME folder.

The Chronoswitch folder must be placed here:
X:/PSP/GAME/