Using any Android phone for recording video or audio it will not allow you to use external microphone or line input , but with simple modification you can enable the external microphone
just by adding 6.8k resistor to both microphone wires will mute the internal microphone , and enable for external source inputs.
In video voice recorder were used for testing , internal microphone still found enabled while inserting the jack,
But by adding resistor found that internal microphone disabled
KSF Electronics 