Hi! Based on eHenry's instructions I have created this patch which I have tested on Debian's 4.19 kernel now on experimental, where we have already enabled the sound driver which was not working.
The result is that with this patch the sound is finally working, so, please apply this to the 4.19 kernel to enable sound. --- bcm283x.dtsi.orig 2018-12-03 00:07:55.000000000 +0100 +++ bcm283x.dtsi 2018-12-05 13:36:02.718569539 +0100 @@ -634,6 +634,10 @@ vc4: gpu { compatible = "brcm,bcm2835-vc4"; }; +audio: audio { + compatible = "brcm,bcm2835-audio"; + brcm,pwm-channels = <8>; +}; }; clocks { Regards. -- Santiago García Mantiñán