How to Get your PSP to play your ISO or CSO
Did you know that you could make an ISO or CSO image of your PSP UMD and then run it off your memory stick. This solves space issues and the games even run faster! What you need to do is first go to the root of your memory stick and make a folder called 'ISO". Put the ISO that you've made from your UMD into this folder and then startup your PSP. In the PSP menu go to 'GAME' and then launch the custom firmware enabler. Inside go into the settings menu and into configuration and change the UMD mode to the m33 driver. You can also do this when in the PSP menu by pressing select to bring up the menu. Now having done this, go to 'GAME' again and just play the ISO. It should work now.