What you need
1 x Sony (original) battery
1 x replacement battery for your PSP
1 x small pin
1 x 512mb memory stick
Step 1: Taking Apart Sony Battery
Be careful not to cut yourself or to dig to hard into the side of battery because there is chips in it and you should not damage them. (not sure what they do, but do not damage them).
Step 2: Finding Chip
You will want to remove the leg on the top left of this diagram.
(-) # -
- # -
- # -
- # -
Also found this video
Step 3: Download
unplug battery again and transfer the following files onto your memory stick.
So now you do a bit of downloading
Download (NEW)(FAT+SLIM files 3.80 m33-5)
Download(FAT+SLIM files 3.71m33-2)Download(FAT+SLIM files 3.71m33-2)]
Video in last step explaines the loading of this onto memory stick much better than i could ever write.
Step 4: Loading ISO
You must have cd in psp when loading otherwise you will get errors when loading game from memory stick.
If loading software you must get software that works with firmware you have.
Hope ya like this