Originally Posted by mr.yastrub
Hey. I have been spent 3 nights in trying to unlock my device.
I recieved next device: I337, NB1, 4.4.2
What i do:
1) downgrade NB1 to MK2 and root
2) load modem MDL
3) trying to unlock throught RegionUnlock ( recieved "could not locate csc data")
3 trying to unlock throught ServiseMenu ( nothing. "Please enter unlock code")
I'm desperate. Please help me!!
Use the Hidden Menu .. I unlocked my device first try. Dont use region unlock.
After samsung blocked the hidden service menu unlock for s4 i am bit worried .but today i found out new process to unlock for free in a website
Step 1: Launch the Phone app on your Galaxy S4, and dial in: *#0011#
Step 2: Press the Menu button followed by the Back key. Then, hit the Menu button again and select KEY INPUT. Enter 1 and press the OK button to enter ServiceMode.
Step 3: Press Menu one more time and tap back again. This will pull up the Main Menu for ServiceMode. Tap  UMTS.
Step 4: Now select DEBUG SCREEN, followed by  PHONE CONTROL.
Step 5: From the next screen, pick  NETWORK LOCK.
Step 6: You’ll get three options. Hit the one that says  PERSO SHA256 OFF.
Step 7: Now, you need to get back to Main Menu. To do this, hit the Menu button followed by the Back key. In Main Menu, now pick COMMON, and then  NV REBUILD.
Step 8: The phone will tell you that a Golden Backup exists. Tap  Restore Back-up.
use this link