Egy nem hivatalos javítás, működik!

0. You need root.
1. Edit /system/etc/audio_platform_info.xml
Under line <acdb_ids> add this:

<device name="SND_DEVICE_IN_HANDSET_MIC" acdb_id="1"/>
<device name="SND_DEVICE_IN_HANDSET_STEREO_DMIC" acdb_id="1"/>

2. Edit /system/etc/mixer_paths_qrd_sku1.xml
At middle of file find this lines:

<path name="handset-mic">
<path name="adc1" />

And replace them for this one line:

<path name="handset-mic"><path name="adc1" /><ctl name="DEC1 Volume" value="102" /><ctl name="DEC2 Volume" value="102" />

3. Below find this line:

<path name="handset-stereo-dmic-ef">

And under it add this:

<ctl name="DEC1 Volume" value="102" />
<ctl name="DEC2 Volume" value="102" />

forrás