How to lock any LTE band in Galaxy J7 (2016)?

[AC Question]

Hi,

I have Samsung Galaxy J7 (2016 - Exynos 7870) which is running on Android Marshmallow.

I wanted to lock B40 LTE band but I can't find any way for it. I tried *#0011# and then put different values I got from the Internet but no one worked. I guess it doesn't work on MM.

So, if possible, please tell me a way to lock specific LTE band in this device. Thank you!