update to 3.10oe-a custom firmware, johnthehun posted the link above for the easy installer. it's just the same process again but this time there's no HEND or idstoragechange.
formatt you memory stick again before you start, run the installer, select your psp path again and install the files, then run the upgrader from the game/memory stick.
after its all done and your at 3.10oe-a formatt the memory stick again and job's done.