x2.3 mod won't take a flash from cromwell

[Berzy]

just finished putting in an X2.3 in and went to flash the bios to romove cromwell from it with the same dvd-r that i've used 50 times and it won't take. the xbox seems to got through all the motions, i put the dvd-r in and it recoginizes the bios.bin file it starts to flash, it finishes it's job shuts down and when i boot back up the cromwell bios loads back up as if it were brand new again.

question is how do i fix this or is it a sour modchip.

thanks in advance.