Hi, i'm french so excuse me for my english.
I have the same problem, the sim-1 slot is on USA BAND.
Did you find a solution?
I'm trying with motorola assistance but for the moment there is no solution.
While trying to force the Sim-1 slot to WCDMA only using 'Phone Testing' feature in my Moto X Play, I accidentally selected the USA band in 'Select Radio Band'. I was trying to force the network mode of Sim-1 to 'WCDMA only' as 3G network in my area is slow and erratic and the phone switches automatically to 2G when the 3G signal is weak even if the presferred network is set to 3G (only preferred network can be set to LTE/3G in the phone and no 3g/WCDMA only option is there). After selecting the USA band the Sim-1 slot cannot detect a network even if the sim is detected. Even a factory reset could not solve the problem. I live in India. Now I am clueless how to rectify the problem. I have read about the possibility of solving the issue by flashing the memory, but am not sure how to do the same.