Here are a few options:
A modern, reliable tool that is officially recommended by the xemu project. It is available as a web-based tool or a command-line interface for Windows, macOS, and Linux. xemu iso to xiso
Open the ISO in a hex editor or use a command: Here are a few options: A modern, reliable
Or, depending on the specific utility and its options: xemu iso to xiso
A long-standing GUI tool for Windows that is popular for managing Xbox ISOs, though it is no longer actively maintained. Step-by-Step Conversion Guide
