Headphones don't work with Andorid 6.0 on BPI-M2U

I am new to Banana Pi and just loaded up the board to the native Android 6.0 installation. I hear the boot sound as it loads the OS, but then I don’t get any more sound through the headphones. Could the output be switching to HDMI( my monitor has no speakers)? How do I fix this? Thanks! McFrisch

I tried converting HDMI to DVI(with no audio output) but it was same. There is no analog audio output from headphone jack. The volume control in Control Center in Linux shows dummy audio output as default, so looks like audio driver is not loaded. The driver module might be added if there is source package available, but doing this for android is something I have never done so it seems that the analog audio output have to be dead for now.
I checked the bluetooth headphone is working with HDMI display.