Problem: I bought my M8 a couple months ago and everything was great until two months ago, one of my friend told me that she couldn’t hear what I was saying. It was a complete silence. I asked different people to call me, and the problem is the same. The thing is, I can still hear everyone but no one can hear me unless I yell at the speakerphone, or use the headset to talk. I tried to restart, then reset the phone, then update the newest version, blow in the bottom mic, and clean the hole, but nothing works. It’s really got me frustrated. I mean whenever someone call me, I gotta find a headset to plug in, and by the time I do it, it takes too long and they hang up. So what should I do next?

Solution: If you already updated your software, did a master reset, and clean the bottom mic then the problem may already be with the hardware. The microphone of your device may already be faulty and will need to be replaced. Your best option is to bring your device to an authorized service center and have it repaired.

Read more at http://thedroidguy.com/2014/08/fix-common-htc-one-m8-problems-errors-part-5-96801#Obv0JwCaZtzeVdXT.99