ARGH, cant get xbox bios to flash

[cavalierguy]

hey guyz, my buddy chipped his xbox but cant get it to flash. It boots to the bios screen fine... then he burned the bios file to a CD-RW between 2 50mb garbage files. but when he loads the CD-RW it will say loading then itll just lock up. once it said erasing bu then it just hung there and didnt do anything. the xbox works fine still, just cant get it to flash. what is he doing wrong? anyone?