While I was working in Korea, I bought a Galaxy s3 SHV-E210 (Korean Model) cell phone. When I bought, I was told that I would be able to use it over here in the States. AT&T was able to put a sim card and activate it on their network, however I only get 3G. The Sales rep told me that the bands for 4G/LTE are different in Korea than stateside carriers, so I may, or may not pick up 4G/LTE. I've done some research and found that the band in the phone can be changed using certain codes. When I enter *#9090# it brings up a menu, I've tried changing some of the 4G/LTE, 3G options in that menu but I never get 4G. I know how to root and put custom firmware on devices, so if that is something I need to do then I am comfortable with that. Can this phone be changed to get a 4G/LTE signal? are there any more "codes" that I can enter in to get any other options that will help me? has anyone here ever change the band on their phone to work on 4g? Thank you for any and all help.