So I got a hold of my friend's PSP phat and made a pandora's battery with his phat battery. Fits in my PSP slim just fine and I also got a mms using RainMMS with the 1.50 PBP firmware. I gave it a test on my friend's PSP. It started up the service mode just fine, but when I did it on mine, it didn't do anything. If you need to know, my PSP slim has the 4.01 OFW, model is PSP-2001