I emailed them 4 times, never got them to respond even after replying to the email saying my boostbox had been delivered.Do you have the standard boost box XDF? If so that's all you need, you don't need a specific flex fuel one. Just switch to the boost box one, set the toggles, and switch back to the standard flex fuel one when you're done.
If you don't have the standard boost box XDF, just email Motiv and they'll send it to you.
Use the BMS BEF xdf’s, they have them in there