Do a network update & make sure that your on m33 update in recovery before you do.Then go to downloads/official firmware on this site& put it in the update folder in PSP/GAME folder of your psp.Then go to game & start tbhe update & you should have 4.01m33-2 but you must have 3.80m33 or higher to do it this way.If you are on official firmware you need to make or buy a pandora batt. & make a MMS first.Check guides/hardware/pandora
http://www.pspmod.com/forums/psp-har...ery-guide.html (Easy-To-Use Pandora's Battery Guide)