Ok, I have i317m (from what I understand the m at the end of the model# specifies that it's Canadian version, which I have). This is Canadian version of Note II, but I thought the Canadian version and the AT&T version use exact same modem and just labeled differently.
I am really novice at this so I'll just list what I did.
1, Flashed with firmware "RWC-I317MVLUDNF1" (Stock KitKat for i317m) with odin
2. Flashed with TWRP (openrecovery-twrp-2.7.2.2-t0lteatt.img.tar)
3. Restart the system. confirmed the SIM works with data and everything working fine
3. Into Recovery mode -> Factory reset, wipe and all that
4. installed "eZKAT_v2.0_n3feat.zip"
5. Restart and no SIM
So If I just get rid of the modem.bin from the zip file, it will keep the current "modem" settings?
I think I will give this a go, whether or not if i get an answer.