I found a cute little tutorial here on how to create a Jigkick / Pandora Battery / Stick. Took me a bit to follow through with the whole procedure, but it was well worth it. Now I can upgrade/downgrade any PSP, no matter what firmware it is currently running. Nice to be able to switch so easily between the official firmware and the “open” firmware that allows homebrew software to run. Also nice to be able to “upgrade” other peoples PSP by simply putting my battery and memory stick in their PSP and pressing a button, takes about 5 min. tops.
Downside is that for some reason my system name and wifi setting get copied to the PSP when upgrading, as far as i can tell the rest of the setting get set back to factory default (e.g. menu background). Nice to be able to play around with my PSP without fear of messing ob something beyond repair.
http://www.psp-hacks.com/forums/post-1202693.html