After installing v6.1 blue, I couldn't make or recieve phone calls.
Blue is awsome but when i pressed the dial button, phone just went back to recent call list.
Incomming calls stright to voice mail.
I checked flight mode turning it on and off, but no good.
I had same problem on previous version but flashed n9 because i had just flashed it prior to this install.
This time reverting to default worked fine.
I'm available for questions if you have them.
Otto