I'm an expat in china and I just purchased a samsung infuse 4g from HK, then came back home and found out that china is not up to 4g speed. The phone is locked and cannot read my chinese sim card i.e., "No SIM card in phone." I asked the phone tech to flash/reset the phone to unlock it and he said all it needs is a different sim card reader. Does that advice make sense? Wireless, the apps etc., work w/no problem. HELP! :