My phone, Samsung G920FD aka Galaxy S6 Duo works with band 3 LTE yet lately (two days ago), it sudden stops to work on this band, it simply doesn't connect to it while my other phones connect to band 3 just fine. I tried installing other SIM cards on this phone, and none of them work (yet they work on other phones). The only thing I did was to install a SIM manager on my device to switch between two SIM cards. I don't think this causes a LTE failure. I've tried doing a hard-reset as well as flashing the ROM (to three different versions, my original one, FrankensteinS6, and OFFICIAL LineageOS 14.1). None of which works. Is it possible that my LTE chipset or other hardware broke perminently? Is not, how to fix it?