So what your saying is if I download the v21.1 I will get TP volume button. (I am pretty sure I never had it to begin with.) Once getting the TP volume button to fix the nav volume I can then reinstall v31? (Won't it get over written then by reinstalling a higher version?) I was also reading on the board that the nightview had some errors is that fixed or it won't matter to my MK3? Thank you again... you both have been extremely helpful and I appreciate your time