Searching today leads you to dead RapidShare links from 2012, Reddit threads on r/360hacks, and obscure Russian modding forums (like xlteam or realmodscene ).
Playing Mayhem 3D wasn't as simple as buying a disc. It was an enthusiast’s endeavor. Users had to flash their disc drives (Lite-On, BenQ, Hitachi), solder the exploit points onto the motherboard, and navigate complex software like FreeBoot or DashLaunch. Mayhem 3D -Jtag RGH-
A JTAG or RGH (Reset Glitch Hack) console allows you to run this game directly from a hard drive or USB, bypassing the need for the physical disc. Searching today leads you to dead RapidShare links