It seems to be the typical 8210 network problem
 

I unlocked my 8210 V5.28 with eeprom tools 3.1; a week later I realised that the phone lose network when talking or suddenly, but not always...it happens once a day or so. I don't know if to unlock the phone is the cause of this wrong working.May be only a casuality.

in other forum people told me to ensure that the antenna is correct, or update The FAID, update the phone... but i dont know how to do this

Can anybody help me?

thank you.

seems more hardware related not software mate

try reflux or reheat the PFO and antenna switch

br
alv

it has been repaired by an oficial site. It was a hardware problem, they change cobba and duplexor...now it works correctly

thank you