[AT&T Samsung Galaxy S 4 General] iquit040:
Step by step to get to tmobile without hiccups (newer baseband - region lock away)

After doing the mdl hidden menu unlock, doing an odin update to the NB1 removed it. So i have been fighting to get it to be stock, run tmobile rom, be on nj4, and unlock via region lock away. Follow this process step by step and will work without my hours of headaches :) I tested this on two att s4 's , please let me know if this helps anyone. Just want to give back considering all of the help I get from the XDA community, and this forum gave me most of the foundation to make this even possible. Thanks Joseph230 for putting this thread together in the first place. My Fiance has been nagging about having att software, no tmobile apps, and non working hotspot, now she can finally leave me alone ;)

You will need to copy these files to your sd card:

I337_NB1_to_NJ4_OTA_Update.zip

M919_NH7_for_I337_NJ4.zip

I337_UCUAMF3_Modem_RockRatt.zip

I337_UCUFNJ4_Modem_RockRatt.zip

ATT_NJ4_modules.zip

Safestrap-JFLTE-3.72-kk-B01.apk

Towelroot-v3.apk

rlaway.apk (i don't have the original file name, this is region lockaway 1.3 , i renamed it so i could push via adb... but can download from market)

You will also need to have on your computer:

337UCUFNB1_Rootable_Full_Odin

I337_NC1_Stock_Kernel.tar

I337_NJ4_Stock_Kernel.tar

Reboot the device into download mode : (Power, vol down, and home) press up to confirm

Flash odin image "I337UCUFNB1_Rootable_Full_Odin"

Once it reboots into the system, go through prompts into the system

Enable developer options by going into about device, keep clicking on build number til it says you are a developer, go into developer options in the menu and enable adb connection

when you plug into your computer check the box to allow connection on the phone. then ok

from command line on the computer : adb reboot recovery

From the recovery menu : do data/master reset, then clear cache

install update from external sd card

install the I337_NB1_to_NJ4_OTA_Update.zip (let this run, will take forever, make sure all you see is yellow text and no errors)

once this finishes and reboots into system, reboot into download mode

odin the I337_NC1_Stock_Kernel.tar into the AP / PDA slot

once it boots, use file explorer, find towel root and install and run it (may have to allow unknown sources)

once it completes, reboot into download mode again

Odin I337_NJ4_Stock_Kernel.tar into AP / PDA slot

once it reboots, connect to a wifi network and google account (don't worry this will be wiped out from the system, so doesn't matter which one you use at this point, just need access to the play store)

download and install super su

install in normal mode

it will offer to disable knox, DO IT! :) , you do not need to reboot

from file explorer install Safestrap-JFLTE-3.72-kk-B01.apk

run it, install the recovery, then reboot into recovery

go into the wipe menu, select advanced, select everything besides the sd card

once this finishes, install M919_NH7_for_I337_NJ4.zip

do not reboot, go back to the install menu and install

UPDATE-SuperSU-v2.02.zip, do not reboot, go back to the install menu

install ATT_NJ4_modules.zip, now reboot into the system

once it is booted, go into the memory card and install safestrap again and then reboot to safestrap

install I337_UCUAMF3_Modem_RockRatt.zip , reboot into system after install

install region lockaway if you have the apk, if not connect to google play store and download it)

Grant root access, and run. When it asks to reboot, hit ok, as its rebooting click safestrap recovery

Install I337_UCUFNJ4_Modem_RockRatt.zip

reboot into system.

At this point you can power the device down and put in your tmobile sim card, it will pickup service and everything will work and you are completely updated!