Not sure. I am guessing yes. However, I was able to accomplish enabling Band 2 and 4 TODAY on XT1100. I am on MINT Sim and my LTE works flawlessly.
I am trying to figure out however...to be a bit more greedy
and see if I can somehow add the third band for Tmob and Verizon (12 and 13 respectively) in this puppy. Both 2 and 4 should work with both providers.
Since this is the only thread that every single user from everywhere (Reddit and other sites) keeps referring to, way back from 2015, and since OP has stopped being active, at least on this thread, I am guessing there has not been any updated work on this.
With custom 8.1s, for instance, will flashing a custom over the AOSP I have make me lose my lte privileges? THAT is my biggest question.
Anyways, if you need instructions, the OPs still hold true. I would be happy to tell you again what I did.