The microphone is not working when I do a call with it.
If during the call I use the speaker option, or connect a headset with microphone, it works with no problem.
If I try to record anything with the record app, it works with no problem.
If I dial *#0283# both works, if I hold the phone in call position, and talk, both microphones duplicate my voice, but the second one (top of phone) is actually stronger than the bottom one although is next to my voice.
I have tried using other voice apps, they sound similarly. Curiously, calls through whatsapp do not suffer this problem, only via phone.
Could be a cleaning issue? Could be a noise cancellation issue? A software issue? Is there any way to fix this via software or hardware other than using speaker/headset in all calls?