I did love this handheld a lot. It really got me through some boring as fuck shifts. Riiiiiiidge Racer and Pixel Junk Monsters are the best.
The battery mod involves a new back casing called Power Armour that lets you put in the bigger Vita battery, and there is a PSP memory to Micro SD ribbon cable that slides in the back. Only downside is the memory card can't be removed without taking the back of the system case off, but I pretty much know what PSP games I want at this point. Might be my favorite form factor of all handhelds, its just so tiny.
I have a memory stick pro duo to microsd converter in my psp it's pretty nice, just fits right in the card slot. The only wrinkle I've found is that some games get confused by the storage size being too big and need a blank save to exist before they'll let you save. This is a known problem so save files are available online, though.
i thought the limit on those was like 32GB(or 2 16GB sd cards with the adapter i think)
I have a bigger one in there. Can't check right now because I'm between save points in ff7 but cfw lets you use basically arbitrarily large microsd cards just with that save caveat. Games only seem to check space for saves on first launch, once a save file for that game exists they're happy to edit it.
ah maybe they updated the firmware then, last time i used my PSP 1000/2000 i think it was capped at 32GB, or maybe 64GB.
Got to the world map and saved, I have a 128GB in there now, it's a psp 2000.