Well i know this works on a PC...so it might work on a PSP
Well on a PC there a watch-type battery on the mainboard that holds the BIOS settings on a memory chip
Well i know its not going to be a watch battery on the PSP but something is holding the settings when the battery is out. I dont know if its flash in the psp or what but if it requires 1.2-1.5 volts to keep memorize your settings we're in good shape.
Just fineout where the source is and hit it with a soldering iron.
Am I close to figuring this out?