The problem started on the second update to WP8.1. Mic does not work, so people can't hear me talk and voice contorl/ Cortana does not 'hear' me. Also, there is zero sound output via either the speaker, headset jack or bluetooth. It's truly deaf and dumb.
I have downloaded and installed the Nokia Software Updater for Retail. It automatically detected and seems to have correctly installed the correct ROM (RM-820), which is ATT, since I see all the ATT bloatware. Yet the problem persists.
This is my work phone and I urgently need it.
Any help appreciated.