i think u will find that u have a 1.6b xbox m8, check the ram on motherboard u will find its hynix, flashbios 303 dosent work on a 1.6 xbox only a 1.6b, as for your problem im having the same thing here, starting to wonder if i might have a faulty chip as its not a common problem and if i try to flash a 512k bios like just cromwell it flashes to both banks, andway the way i found to get past my problems was to make a full 1mb bios of m8plusv16, then flash that to the chip and it stops the clock resetting, though i still find the xbox to be buggy, slow loading times and dvd player wont play movies good, keeps freezing or stopping and starting, remember if u make a full 1mb bios u wont have flashbios on your chip nomore, but u can still reflash through a programmer or evox has flash option (standard evox not slayers) or theres other flash progs about u can run straight from evox...
let me know how u get on, and if u have dvd player installed does yours stop and start on dvdr
DcMaD