I'm on slimkat ROM version 7 4.4.4 and I have no LTE.
It started yesterday. I usually just have 3G switched on all day at work to save battery but when I get home I like to stream music and YouTube etc so I flip on LTE. I went under "mobile networks". Mine shows in order: LTE (recommended), 1X, 3G, and Global. From prior experimenting I know that "Global" is actually LTE for me. Turning on "LTE (recommended)" setting actually makes it so I cannot receive calls, 1X is obviously 2G and 3G is 3G. Anyway, starting last night when I came home I noticed when I switched to Global setting my signal went out, all bars disappeared and then came back on seconds later and only showed 3G. Speeds were 3G. My wife has the same phone unrooted and shows LTE Spark on her device so I know its not a lack of LTE in the apartment. What is going on???

 

I tried that but I'm still showing 3G

 

I ended up taking to a friend who reflashed NC6 stock and rerooted it. I've got LTE back!

 

One thing I will say is that ever since I had NO flashed my battery life took a dive and the Android update has installed and keeps popping up. I wish there was a way to Install it and also keep root. I miss the battery life of slimkat