A while ago i gave my psp to my friend to borrow it had 3.73M33 Firmware but he decided he wanted to downgrade it or something i have no idea what he's done but now my psp boots to a black screen. I'm Pretty sure he did something along the lines of pandora because my friends phat psp battery works on my psp.
Is their anyway to fix this or do i have to buy a new battery?