I tried to reformat / restore my z ultra, unfortunately the issue still remains.
I cannot stop busy tone by pressing red button even when somebody rejects my call and keeps on a bust tone.
Also I encounter this odd issue today before I restore... Suddenly, I cannot turn on the screen, I pressed power bottom but nothing happens, but I can receive sms, call, email, messages, but the screen stays in black. I had to force shutdown the phone power + vol up and start the phone.
Anybody encounters this?
Sent from my C6833 using xda app-developers app