Critical controls (Fallback_Ramp & Master_Ramp) are set to naught (0) at each boot by the 4a unicens hal.
So there is no sound coming out of the card (muted).
$ amixer -D hw:ep016ch cset name='Fallback_Ramp' 100
$ amixer -D hw:ep016ch cset name='Master_Ramp' 100
$ speaker-test -D Emergency -c 6 -t wav