Audio and Internal Mic

Audio

Mojave has removed a lot of layout IDs from its AppleHDA.kext, the currently most recommended way of patching AppleHDA.kext is AppleALC.kext. Get the latest version from here.

Internal mic

Unfortunately, the internal microphone does not work out of the box even with this kext. You need a patch to get it working. I use CodecCommander.kext and add a profile for CX20752 in CodecCommander.kext/Contents/Info.plist (General guide):

<key>14f1_510f</key>
<string>CX20752</string>
<key>CX20752</key>
<dict>
  <key>Custom Commands</key>
  <array>
    <dict>
      <key>Command</key>
      <string>0x01970724</string>
      <key>Comment</key>
      <string>0x19 SET_PIN_WIDGET_CONTROL 0x24</string>
      <key>On Init</key>
      <true/>
      <key>On Sleep</key>
      <false/>
      <key>On Wake</key>
      <true/>
    </dict>
    <dict>
      <key>Command</key>
      <string>0x01a70724</string>
      <key>Comment</key>
      <string>0x1a SET_PIN_WIDGET_CONTROL 0x24</string>
      <key>On Init</key>
      <true/>
      <key>On Sleep</key>
      <false/>
      <key>On Wake</key>
      <true/>
    </dict>
  </array>
  <key>Perform Reset</key>
  <false/>
  <key>Perform Reset on External Wake</key>
  <false/>
</dict>

Alternatively, you can use the script I created to apply this patch automatically.