No sound from 5.1 movies on Raspberry Pi 3

1st Official Post

    Hi,

    I'm running Libreelec 7.0.2 on a RPi3. My problem is that I don't get any sound when playing any video source that has 5.1 audio - movies with stereo audio is fine.

    Weirdly, if I replace the RPi3 with an RPi2 then the sound works as expected (same setup, just replaced the RPi3).

    This smells to me like a configuration issue with the RPi3, but I can't change any of the configuration since Libreelec locks this down (for good reasons).

    When I look at the guisettings.xml file, I see that ac3passthrough is set to true, even though it's off in the settings. (also, transcode AC3 is off). If I manually edit the file and set AC3 passthrough to false and transcode to true, the values are reset when I play the movie. :(

    Clearly I'm missing something. Any clues on how I proceed with solving the problem?