If you ran it:

Simply copying an ISO to a USB drive as a single file usually results in:

iso2opl splits the ISO into smaller fragments and arranges them for sequential reading, drastically improving speed and reliability on slower storage.

ISO2OPL is a Windows tool that converts standard PS2 .iso files into the fragmented, OPL-friendly .iso or .usz (compressed) format used by Open PS2 Loader over USB, HDD, or SMB.

iso2opl.exe represents a significant chapter in the history of PS2 homebrew. While it has largely been superseded by GUI-based applications like OPL Manager and USBUtil, understanding it provides insight into the technical requirements of the PlayStation 2 file system. If you are maintaining a legacy setup or prefer using command-line scripts, iso2opl.exe remains a functional and reliable tool for managing your PS2 game library.