You can launch elfs from usb through launch.elf. I have an infinity clone and before that a legit infinity. They stopped making matrix infinity in like 2007 so most people use clones. It's easy to tell because the latest firmware is 1.93. If it says 1.99, it's probably a clone. Don't update or you might brick. Anyway, you can launch launch.elf by creating a boot.elf. I've forgotten the specifics but essentially each boot.elf is tied to the r and l buttons. Iirc, boot.elf is r1 by default. I've never gotten a black screen so I don't know what could be wrong with that person in the link's setup.