go to arm section of mode and hit the add range button and flick the switch you want as arm and see what the beta flight thinks that switch is. when you choose the aux chooser, flicking the switch should change the aux# to that switch, or at least theres a way to make it do that for you. on my controller for some reason I cant get aux 5 to not be the failsafe (front left 2 position switch) Maybe yours has something like that too. I had to make arm another switch, even though i wanted that one to be it.