Step 1: After downloading the file above, connect your CFW PSP to your PC via USB mode and locate the Root directory of either your system storage or memory stick.
Step 2: If you haven't already, create a folder called ISO on the memory Root and copy the Fullmetal Alchemist CSO file to his folder.
Step 3: Exit USB mode and access your PSP XMB and hit the SELECT button and make sure your M33 driver for your ISO image is enabled or else your game image wont run, Also recommended to overclock your Game CPU to 333/166. Then run the game from your Game section on your XMB
NOTE: If the CSO doesn't run, access the Recovery menu and go to configuration and select Fake Region and change it to Europe because it a Euro signed CSO. This might happen on ME CFW.