How would I go about purposely disabling all microphones on an Android phone? I'm attempting to repurpose older Android phones, and I'm looking for a way to disable the microphones to avoid having spy-accessible microphones all over my house.

Is there a way of removing or purposely breaking the microphone drivers without breaking the ability to play audio?
I can not see a purpose for this but ultimately the easiest method if you never want to use the microphone again is to just break the microphone with a small pin or something,
 you could disconnect them from the motherboard altogether and rebuild the device with no microphone...     

I'm recommending hardware based solutions because it's ultimately the safest method of complete removal....         

If you are familiar with the mobile phone security protocol "SS7" and you have read your mobile phone provider's terms and conditions then you'd be aware that you don't actually have the legal right to remove the ability for police or other law enforcement agency's  to have access to the microphone ( even while your device is switched OFF )  ... This is clearly stated on most or all mobile phone provider's term's and conditions ... 

The main reasons you can't legally do it ( without an unexplainable hardware fault - I strongly discourage tampering with your device )    


You don't actually BUY the device, you ONLY buy the RIGHT to USE the device from the company or copyright holder.   
You AGREE to ALLOW police and law enforcement angecys to have access to your microphone even while your device is switched OFF    

So now that's clear, 


This solution is provided for Educational use only.