I have searched and talked to one dealer and no help, i had 4.0 i have a 11" Lf coil and 5x9 HF coil, both ran great on 4.0 then i updated to 5.21 and on both coils i get a lot of static or EMI and they won't settle down. I would like to keep the 5.21 update for its improvements, i have reinstalled 5.21 several times it says its updated to the control when turning it on it comes up 5.21. I thought i would install 4.0 just to see if everything was as good as it was before but can't figure how to go back and do that, gary's video says just hit the dropdown box and select 4.0 but there is no dropdown box.Please help me get my deus back!