V4 amp volume control bug

hi everyone, i have four Up2Stream 2.0 V4 amps and since a few days I can’t control the volume any more, either via Spotify connect or 4stream app. the volume is either mute or full volume, even a tiny bit after mute is full volume. how can i fix this? the setup was working flawlessly before…


already talking about this here

resetting to factory settings worked for a bit but then the problem keeps coming back, you have to find a solution for this!