What KitKat ROM are you running that has 4g that works?
I am currently on Vanir and cannot get it to work. I have tried different APN, different radios (GA02 and GJ04). I have gone into *#*#data#*#* and turned on LTE. I have gone into *#*#4636#*#* and I am on GSM/CDMA auto (PRL). I have gone to networks settings and selected LTE. NONE of the settings stick.
I had 4g working at one point on CM 11 Playfulgod edition but I can't remember exactly what I did to make it work. So I am looking for other Ting users that have 4g working and what ROM you are using.
Galaxy S4 SPH-L720
Kernel: Vanir Stock
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