Is this white Star Wars PSP a fat or a slim ?
Either way, you'll need a Pandora Battery and a Magic Memory stick to downgrade your PSP. You can get this by
1. Downloading some files, and getting someone you know with a PSP already on a CFW to modify a battery and memory stick using those, so they then become a PB & a MMS
2. Make the MMS yourself using some files, and then hard-mod a battery pulling a pin or something or other.
3. Make the MMS yourself using some files and then buy a pre-made Pandora Battery which goes by the name of a Datel Tool Battery.
Once again, it's 2AM so I can't be arsed finding any links for you, but there's literally guides everywhere.
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