So my friend has a PSP that is version 2.5 currently but he bought it when it first came out. I want to downgrade it to 1.5 so do I just use the method using GTA etc? I want to downgrade for him but my concern is whether I need to know what his firmware was when he first bought it, or whether it doesn't matter and I should just downgrade according to what his firmware currently is. Let me know! Thanks!