PSP:Chronoswitch

Chronoswitch is a homebrew PSP utility that allows a console to freely upgrade and downgrade official PSP firmware. It is mainly useful for reverting a cIPL or Infinity console with PRO/ME CFW to OFW for installing cIPL ARK-4, or downgrading fron 6.61 to 6.60.

The following guide has instructions courtacy of the pspunk.

Prequsites

• Having at least 80% battery life
• Fully secured battery that will not fall out
• Ideally, a charger plugged into the system
• A firmware PUP that is 6.20 or newer. Anything lower instead requires a JigKick & Magic Memory Stick.

Usage

1. Download the latest build of Chronoswitch.
2. Get the desired firmware update for your PSP. They can be reached from the following places:
   • Sony CDN
   • Darthsternie's archive
   • Midnightchannel archive
3. Transfer Chronoswitch's EBOOT.PBP file in the file path of ms0:/PSP/GAME/Chronoswitch/EBOOT.PBP on the console's memory stick, with ms0:/ being the root directory.
   • If using the PSP Go's internal storage, ms0:/ instead becomes ef0:/.
4. Transfer the firmware update file to ms0:/PSP/GAME/UPDATE/EBOOT.PBP on the console's memory stick, with ms0:/ being the root directory.
   • If using the PSP Go's internal storage, ms0:/ instead becomes ef0:/
   • If your update file is named something like 6.61.PBP, then rename it to EBOOT.PBP
5. Launch the Chronoswitch application and follow the on-screen instructions. Once completed, the PSP will restart and will now be on the official firmware version that was chosen.