It is widely supported by Open PS2 Loader (OPL) versions 1.2.0 and later, as well as some modern PSP custom firmwares and emulators. Top ISO to ZSO Converters (2026 Update)
Users seeking a fast C++ alternative to older Python scripts.
On devices with slow storage interfaces, such as PS2 USB 1.1, ZSO can actually improve performance because the console reads less data from the drive, reducing stuttering in FMVs (Full Motion Videos).
LZ4 decompression is extremely fast, often described as equivalent to three memcpy operations.
ZSO (Compressed ISO) is a disk image format designed for retro console emulation and homebrew loaders. Unlike the older format, which uses DEFLATE compression, ZSO uses LZ4.
A high-performance command-line tool that supports CSO, ZSO, and other formats. It is highly regarded for its precision and speed.