A reliable, modern command-line tool (with some GUI front-ends) for extracting or repacking ISOs into the more efficient XISO format.
If you have a full ISO and want to compress it yourself, several specialized tools are recommended by the community: xbox roms highly compressed
Frequently used for Xbox 360 ISOs to extract them into folders, allowing you to skip bulky system update data. Is It Safe to Download Highly Compressed ROMs? A reliable, modern command-line tool (with some GUI
A modern "all-in-one" manager for the Original Xbox. It can convert dumps into CCI format or trim unused space to create reduced-size ISOs. A modern "all-in-one" manager for the Original Xbox
A repackaged format that removes the security padding and system update folders. These are often significantly smaller and are the standard for emulators like Xemu .
A newer, more advanced compression format used with the Cerbios BIOS. It maintains the original disc structure while "zeroing out" padding for maximum space savings.
While compression is a legitimate technical process, "highly compressed" is often used as clickbait by malicious sites. Team-Resurgent/Repackinator - GitHub