This stick operates very clever way in my Ultimo. If I set preferred tuner to auto, Ultimo uses A-tuner for DVB-T SD-channels, but when I go to T2 HD channels, it automatically switches to tuner D which is Sundtek. But in DUO2 this does not happen. I have to set Sundtek (tuner C) as preferred tuner. Both boxes have OpenViX version 808 and latest VU+ drivers.