I made a serious mistake and would like to help. I learn about command *#*#4636#*#* and try it. I did make a stupid mistake when click on "Select radio band" in "Phone information" section, then I click on "USA band" under "Select GSM/UMTS band". Then my GSM functionality has gone. That is very stupid as I am current using a GSM sim (i am not in the US). I have to do a factory reset and my D2G can use GSM sim again, but no 3G function. Even I change network setting to WCDMA only, there is no network coverage. If I change back to GSM only or GSM/WCDMA auto, there is only GPRS, not HSDPA.
How can I get my 3G function back?
Thank you very much.