Before I start this is how I rooted MY phone and a few friends as we all wanted to test out Verizon's new VoLTE only on Android 4.4.4. I Just fallowed other guides (Links below) To get this to root my phone and did not do any of this without XDA help.
If you wish to use VoLTE fallow the link here:
DO NOT DO OTA! To NHA IF ROOTES OR EVER ROOTED
The ota update should fail, if it does not you might get stuck on a bootloop and need to reset your phone. this happened to me and someone else I was helping.
Files To Download:
https://www.androidfilehost.com/?fid=23622183712472866 (Unzip NI2_stock_kernel.tar.md5)
Pre: Install Towel Root prior https://towelroot.com/ if you have not already.
(Step 1 is Only If your not already on NHA or made changes beyond rooting to your device)
1. Update To 4.4.4 using G900VVRU1ANHA_G900VVZW1ANHA_VZW.zip, Extract the files and select it in AP under Odin. Turn off your device and hold DOWN VOLUME + HOME + POWER to get into Download Mode, you phone should show up in Odin if it does not, then manually download the drivers from Here
2. Once your phone shows up on Odin press "Start" and wait a few minutes.
2.5 NEW STEP: Take OTA to NI2.
3. Once your phones starts put it back into download mode, and select G900V_NCG_Stock_Kernel.tar.md5 under PA and Click start and wait a few minutes.
4. Once your phone restarts you may notice some apps will start to fail and force close, this is why I had you install Towel Root prior so we can get in and get out, Press Ok or Force Close continuously if necessary until you get Towel Root open and "Make it rain". Then turn off the phone and go back into Download Mode.
5. Now flash NI2_stock_kernel.tar.md5 and let the phone restart
6. Everything should be good! (: Enjoy and message for help.
I am not responsible for what happens!! Well unless you get it working 100% and are happy. But There is a risk