To me, the AC-3+ passthrough audio is really a big issue... I currently have a Qviart Lunix 4K connected (HDMI CEC) with a Denon AMP and TV, using PLI 9.
Everything works fine if I leave audio in the downmix mode but, of course, no Dolby audio would be available.
Most channels are broadcasted with either MPEG, AAC or AC-3 audio, and there are no problems in passing-through the corresponding audio to the AMP or the TV.
Conversely, one provider broadcasts AC-3+ (Dolby plus) audio only, and I found no way to passthrough them to the AMP. If I switch the audio of the various channels to and from the passthrough/downmix modes, then the audio signal is gravely disrupted and I need to restart the box in order to restore a normal audio signal.
So, it would seem that AC-3+ audio is not supported by the box. However, and very surprisingly, if I play a mp4 recorded file having the AC-3+ track only, then the audio works great in passthrough...
Therefore, the problem should be in the software rather then in the hardware... however none of the various E2 images I've tried so far were able to address the issue.
Any suggestion to fix the issue or to buy a new E2 box that works better with Dolby Plus?