I'm sure this is a stupid question. But I got to know. I just installed 3.71 M33-4 on my PSP. I was wondering if I can play UMD games on the PSP. Sometimes depending on the System software a PSP is running, a UMD game will say you must install the new software to play it. All my games are in ISO or CSO format so I play them off the memory chip. I don't want to risk messing up the 3.71 m33-4 system by playing a UMD game.