There are no known white DuoX2 clones so you are pretty safe. As far as it goes with the bios, are you maybe confusing the bios and dashboard???
Cause if you get to the flashbios screen then it obviosuly reads your chip, and if it gives no errors, then it flashed the chip ok.
When the Xbox logo comes up, does it still say "MS" at the bottom, or does it says Xecuter rock my box, or something different. Just wondering cause if you flash the bios, but some install a different dashboard, then it will still go to the MS dashboard and appear to not be modded.