Problems with audio via bluetooth connect to car

[zkajdan]

Hi,

I've experimented with different distros trying to get audio output from the car MMI. Connecting via bluetooth worked fine in all cases, but either I did not get any sound or I was unable to tune up the volume (the car MMI saying "functionality unavailable this time" when turning the volume knob).

Has anyone gotten this to work, and if so, could you let me know which OS you're using?

[qcomment]

I only experience quite frequent BT connection loss issues using the Pinephone on VW2021 MMI, making it troublesome while driving.
Otherwise it seems to work ok using PMOS and Audacious (being the somewhat the only usable player with the screen resolution of the pine, also displaying track info.
lollypop worked also, but did not display track info iirc.

Looking for a way to "mirror link" the phone, but that seems cert. date workaround troublesome if any.