What about the ./mic_energy demo ?? It could be easier to see is the microphones are working. Also you can use the micarray_recorder to test mics separately.
So I asume that if micarray_recorder is working you are getting audio records from the individuals mics. About the mic_demo not working, be aware that this demo require you to do some kind of laud noise like claps or finger snapping to produce a change in the values. For example: