Recording through built-in iPhone mic while headphones plugged in

Hi!

I am having following problem:

I would like to record my acoustic guitar on iPhone (7+) using GarageBand (v. 2.3.1).

But when I plug in the apple headphones (earPods with Lightning connector), it automatically changes the input mic to the one on the headphones, that is a little shabby comparing to the built-in one.

I need to use the headphones, to overcome recording of metronome clicks, input-monitoring, etc...

Is there some way to change the input source, so I can use the apple headphones, but keep recording audio using the built-in iPhone mic?

Thanks in advance.

Cheers