Originally Posted by Am2am
You'd better choose WCDMA preferred for SIM2
For SIM1 better to choose GSM only , in that case phone will not try to connect TDSCDMA and not spend battery resource
GSM preferred - will use GSM as priority
GSM only - will use only GSM , no other standard will be tried to connect (in case of support, of course)
At least this is the theory.
Which in this very phone doesn't reflect the real world behavior, try to set GSM only on SIM2.
The phone will switch to gsm, then will switch back to WCDMA/GSM in matter of ten seconds.
At least this is what happen on my phone.