: Ensure all .iso and .cso files sit in the ISO folder at the root of the Memory Stick. Partition Error Cause : Corrupted Memory Stick file system.

The tool can extract a digital ISO copy of a physical game disc (UMD) directly to the console's storage.

is a homebrew application that runs directly on a PSP equipped with Custom Firmware (CFW). Unlike PC-based utilities, ISO Tool allows users to manage, patch, encrypt, decrypt, and convert game files right from the console's XMB (XrossMediaBar) interface without needing a computer.

Many old PSP ISOs need to be patched to run on modern Custom Firmware (like 6.61 PRO-C or ARK-4). ISO Tool 131 contains the Prometheus ISO Loader module, which allows games requiring Firmware 6.xx to run on older 5.xx CFW.