I did it before on Pine64 boards, configuring the codec in alsamixer is a bit complicated because it has 113 controls. Looking at the PB schematic MIC1 is wired to the internal MIC and MIC2 is wired to the headphone jack for 4 ring connectors. I'll see if I find some time tonight to play with the settings... it works on Android so the hardware should be good 
Looking at what Android does:
MIC1:
MIC2:
Can someone try to set those in alsamixer and report back? I dont have a PB with me atm...

Looking at what Android does:
MIC1:
Code:
<path name="media-main-mic">
<ctl name="AIF1OUT0R Mux" value="AIF1_AD0R" />
<ctl name="AIF1OUT0L Mux" value="AIF1_AD0L" />
<ctl name="AIF1 AD0R Mixer ADCR Switch" value="1" />
<ctl name="AIF1 AD0L Mixer ADCL Switch" value="1" />
<ctl name="ADCR Mux" value="ADC" />
<ctl name="ADCL Mux" value="ADC" />
<ctl name="LADC input Mixer MIC1 boost Switch" value="1" />
<ctl name="RADC input Mixer MIC1 boost Switch" value="1" />
<ctl name="ADC volume" value="180" />
</path>
MIC2:
Code:
<path name="media-headset-mic">
<ctl name="MIC2 SRC" value="MIC2" />
<ctl name="LADC input Mixer MIC2 boost Switch" value="1" />
<ctl name="RADC input Mixer MIC2 boost Switch" value="1" />
<ctl name="ADCL Mux" value="ADC" />
<ctl name="ADCR Mux" value="ADC" />
<ctl name="AIF1 AD0L Mixer ADCL Switch" value="1" />
<ctl name="AIF1 AD0R Mixer ADCR Switch" value="1" />
<ctl name="AIF1OUT0L Mux" value="AIF1_AD0L" />
<ctl name="AIF1OUT0R Mux" value="AIF1_AD0R" />
<ctl name="ADC volume" value="160" />
</path>
Can someone try to set those in alsamixer and report back? I dont have a PB with me atm...
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