This is a complete idiots guide to everything you ever wanted to know about playing ISO/CSO games on a PSP. Terminology ISO: A disk image file that contains the PSP game. The average PSP ISO file is generally around 1.5 Gigabytes. CISO(or CSO): Short for "Compressed ISO". A CSO is the same thing as an ISO except it is a smaller file size. Some games such as Grand Theft Auto might be a little laggy (slow), but usually not slow enough to ruin your gameplay. CSO are highly recommended for those with memory sticks with a smaller amount of memory (such as 1gb) or those who want to fit more games on their memory stick. The average file size for a CSO is about 600 MB. UMD: Short for "Universal Media Disk". It is the term for the game disks that the psp plays. RipKit: "Patches" for PSP ISO files that significantly reduce its file size by removing the games audio and video. If you are one of those people who like to follow story lines in games, rip kits are not recommended. www.ripkits.net is a good place to find ripkits for your games. Firmware: The "operating system" of the PSP. PSP firmware is like the "windows" operating system for the PSP. Custom Firmware: Created by dark alex, this is a modded version of the psp firmware which is a combination of the original PSP 1.50 firmware with the current psp firmware. Custom firmware is highly recommended to all PSP users. Custom firmware can play ISO and CSO files easily with out having to download extra programs and it also allows users to use homebrew applications/games. Homebrew: "Homemade" PSP applications or games that are just like computer programs. Some can turn your PSP into a universal remote conrol and some can be used to play Super Nintendo Games. Homebrew can only be played on official firmware 1.50 or any custom firmware, although there are some homebrew that work on other official firmware although there are very few. Devhook: A homebrew application that allows users to emulate newer firmwares from there 1.50 firmware. MS: Memory Stick MS0:Memory Stick Root (The main folder of the psp memory stick). Where to get PSP ISO/CSO files You can download PSP ISO/CSO files from almost any torrent site such as www.torrentz.com. Just search for "PSP" and the name of the game you want. To use torrents just download any bittorrent client such as azureus (download at azureus.sourceforge.net), and then open the torrent file with your bittorrent client. It takes generally about a day for the torrent to download the file because of its large file size, some may take a shorter amount of time if they have more seeders. How to Run ISO/CSO Files on Firmware 1.50 This part of the guide is for those of you who have firmware 1.50. Requirements: A PSP with firmware version 1.50 A PSP memory stick (1GB or more) A UMD in your PSP disk drive (Any UMD works) UMD emulator V0.8c http://www.psp-hacks.com/file/92 Devhook 0.52 see tutorial at http://forums.exophase.com/showthread.php?t=295 USING UMD EMULATOR 1. Install UMD Emulator using the instructions in the readme file. 2. Make a new folder in the root of your memory stick called "ISO". 3.Put your ISO/CSO game file into the ISO folder. 4.Unplug your MS. 5. Make sure that there is a UMD in your psp disk drive. 6. Start UMD Emulator and System load your ISO/CSO. 7. Start Devhook. 8. Run your ISO/CSO. How to run ISO/CSO files on Custom Firmware 1.Connect your PSP to your PC via usb cable. 2.Put your ISO/CSO file in the ISO folder of your memory stick. 3.Disconnect your PSP from your PC. 4.Fully shut down your PSP by holding the power switch for about 7 seconds. 5. Boot into recovery mode by holding the R button while starting up your PSP. 6. Go into Configuration on the recovery menu. 7. Change the Game Folder homebre to the 1.50 kernel. 8. Change the "UMD Mode" to "No UMD" 9. Go back to the main menu. 10. Go to Advance. 11. Then go to Advance Configuration. 12. Enable Plain modules in UMD/ISO and Disable "Execute BOOT.BIN in UMD/ISO" 13. Go back to the main menu and click exit. 14. In your XMB go to game and then click on your ISO file on your memory stick. 15. Enjoy FAQ Where can I get custom firmware? The best pace to get it is probably www.dark-alex.org. What programs can I use to compress ISO Files into CSO files? The best program is PSP Compressor. You can get it from http://psp.console-tribe.com/downloads/file-1551/psp-compressor-v12.html. How to I rip an ISO from a UMD? Download DAX UMD Dumper from http://konsolenprofis.de/downloads/download.php?id=1393 When I download a PSP game torrent, there are just a bunch of files in the folder saying part 1 part 2 etc. What do I do? All you have to do is extract the Part 1 RAR file and it will automatically find the other rar files and you will have your ISO.