How do I downgrade from official firmware 3.40 on the PSP Phat 1001. Please do not tell me to use a game because my disk drive doesn't work. So can I use a softmod option? I really dont what to install a modchip because I do not know how to solder and I dont want to void my warranty for just a mod chip. But I need a new screen and a new disk drive so I need to void my warranty on those thing's.