So, I tried to run the app that puts your memory stick drivers to 3.71, and when it said it was finished, I, being the impatient one, unplugged my battery to make it turn off. It wasn't finished, or my fatmsmod.prx was faulty. My PSP now boots to a black screen unless I hold down R to boot to the recovery menu. How do I fix this? Edit: It now only boots recovery if the charger is plugged in.