To play this ISO on a modified Xbox 360, you typically need to convert it into a format the console can read from a hard drive:
Xbox 360 (can be played on original retail consoles if burned to a disc or on modified RGH/JTAG consoles via extraction) Usage for Modded Consoles (RGH/JTAG) BulletStorm [Region Free][ISO]
Use tools like Xbox 360 ISO Extractor or WX360 to unpack the files. To play this ISO on a modified Xbox