Default [Q] G Pro (F240S Korean Version) only gets 3G at AT&T

Hello,

I have 2 questions,

1. I currently have AT&T Gophone LTE plan. I know G Pro supports LTE and I used LTE network with this phone in South Korea. But with AT&T, it only gets 3G. I know F240S supports LTE band 5 (850Mhz) and AT&T also supports band 5. I even accessed the service menu and changed some settings but nothing changes.

2. I have a Sprint account with Unlimited LTE data plan. I heard G pro has multiple versions but the hardware of them is basically same, which means it supports both GSM and CDMA? So maybe I can use my G pro at Sprint? I went to the Sprint store and the Sprint guy told me the device supports CDMA but its ESN number is not registered on Sprint system so it cannot be used with Sprint. Is there any way to use sprint plan?


Thanks