After flashing my BV6800 pro, everything works fine, including data over mobile network. My problem begins when I try to make or receive phone calls, the phone immediately desconect from the mobile network, with the signal indicator on the status bar, going to zero immediately and returning soon after I stop the tentative call. I noticed that after flashing, the imei were missing, but I already fixed that following instructions I found here. Also, the phone model and SN becoming missing on the about the phone section on Android. How can I fix this? I flashed the phone with the latest US version rom from the link available in another topic. Anyone can help me, please?