Struggling with recording audio via the 3.5mm jack


I’m struggling with recording audio via the 3.5 mm jack.

I have tested the audioPlaybackRec application ( and it will only record zeros in the wav file when executed with the following parameters: REC MIC /home/root/test.wav WAV

I have verified that both my mic and speaker works using the mangoVoiceCall application.

Is there anyone that can give me a hint of what is wrong?

I’m using Legato 16.10.3 on the Mangoh Green.


I created a small testa application and solved this problem by starting to play audio to the speaker before opening the mic with le_audio_OpenMic(). This will configure the audio mux (U500) to connect the 3.5mm jack to the internal codec.