I have a radio and a Flarm connected to my smartphone via the wifi serial bridge. I tried to make a quick access button for the radio on the mainscreen. Therefor I used the custom key "device B config" but this did not work. I also tried this with the Flarm, this worked, but very limited. LK8000 version 7.1c on a Nokia 8.
We don't have a custom key for the radio dialog yet. However I never missed it in flight since we can select airfield and airspace frequencies directly from the map. And Config->Setup Radio is not so far away. Compared to XCSoar it is most comfortable)
But I can make a custom key for it in the wintertime.