My ATT E980 lacks the 4G/3G button. If I root the phone, can I switch the phone to 3G or 2G only mode then??? If no, what should I do to fix this ?I'm not in America at this time and I really need my phone to work on 3g, sometimes 2g only mode. The automatic 4G LTE mode looses the signal and interupts my calls frequently. Thanks