How to SIM Unlock AT&T Galaxy S4 SGH-I337 and Canadian SGH-I337M

Thinking of unlocking your SIM-locked Galaxy S4? Well, it’s very easy to get your device unlocked from the bondage of sticking to a single network from your carrier. Just type in the the 2 words “SIM Unlock” in your web search bar and you will be overwhelmed to see the results of sites that claim to unlock your device for a fee.

At DroidViews, we try never to miss a single tip or hacking drill that can not only save your valuable money but also give you the ultimate sense of doing something worthwhile on your own. Earlier we posted the trick to SIM-Unlock  branded Galaxy S4 GT-I9500 and its LTE variant GT-I9505 and today we would share the method of unlocking your T-Mobile Galaxy S4 SGH-M919 and AT&T Galaxy S4 SGH-I337. Please note that the method given below has also been found working on the Canadian variants of the Galaxy S4 from Bell, Rogers, Telus, etc. The credit for discovering the method goes to XDA member Kaleido.

Also See:

How to SIM Unlock Samsung Galaxy S4 GT-I9500 & GT-I9505

Advantages of having a SIM Unlocked Phone

Having SIM Unlocked your T-Mobile and AT&T Galaxy S4, you can-

  1. Enjoy a sense of freedom for Free.
  2. Use your phone with any network provider around the world that means you can use any SIM card from a preferred service provider.
  3. Enjoy a permanent unlocked phone that means the device remains unlocked even after firmware update.
  4. Save money on roaming charges while travelling abroad.


Follow the guide at your own risk. The procedure given below has been tested by many T-Mobile and AT&T Galaxy S4 users and it worked for most of them, we do not guarantee that it’ll certainly work for you too. In many cases, the users make some mistake while following the steps, resulting in failure. Therefore, read the tutorial several times before proceeding and follow the steps carefully. Also, the result depends a lot on the firmware version you have on your phone. Sometimes a software update might sweep away the possibility of your phone being SIM Unlocked.

Supported Models:

The method described here might or not work on all devices due to some new changes pushed (via software updates) by carriers when they discover a working unlock method.  For successful result, make sure you have one of the  following variants of Samsung Galaxy S4. The rate of successful SIM unlocking on T-Mobile S4 is higher than others.

  • T-Mobile Galaxy S4 SGH-M919
  • AT&T Galaxy S4 SGH-I337
  • Canadian Bell, Rogers, Telus, Virgin Galaxy S4 SGH-I337M
  • Galaxy S4 GT-I9505 LTE

Points to Keep in Mind and Workaround:

  • Make sure your phone is on Samsung’s stock official firmware. It won’t work at all if your phone has a custom ROM installed on it.
  • It does not make a difference whether your phone is rooted or not.
  • Also, while you follow the steps, it should have the authorized SIM inserted into it. That means, the SIM from the carrier your device is locked to.
  • The SIM Unlock (if successful) achieved by this method is permanent and survives even after official updates or flashing custom ROMs.
  • If your phone shows “SHA256_ENABLED_FLAG[0]” at Step 9, it means it already allows changes in unlock settings. There is nothing to be worried about it. Just continue with the next steps.
  • What to do if you find “Golden backup doesn’t exist” message at Step 16, or your current command is not “116631”? Try the following workaround:
    • Select  [3] PERSO SHA256 ON after Step 7. Then continue with Step 9 and your phone should show “SHA256_ENABLED_FLAG[1] in place of [0] value.
  • If you find “Golden Backup doesn’t exist” at Step 16, create a backup using option [1] on the same screen and then restore that backup using option [4]. Then wait till your phone reboots.

How to SIM Unlock AT&T Galaxy S4

  1. Open your phone’s dialer and dial the following code to enter the Service Menu on your Galaxy S4: *#27663368378#
  2. If the above code does not work for you, try this: *#0011# (found working on AT&T Galaxy S4).
  3. galaxy-s4-service-menu-00
  4. Now select [1] UMTS by tapping on it.galaxy-s4-service-menu-2
  5. When you get into the UMTS Main Menu, tap on [1] DEBUG SCREEN.galaxy-s4-service-menu-0
  6. This will take you to Debug Screen menu where you have to select [6] PHONE CONTROL.galaxy-s4-service-menu-3
  7. In the Phone Control menu, you will see an option called [6] NETWORK LOCK. Tap on it.galaxy-s4-service-menu-4
  8. In the Network Lock screen, select  [3] PERSO SHA256 OFF.
  9. On the next screen tap on SHA256_ENABLED_FLAG[1].
  10. Doing this will show the following message:
    Current Command is 116631
  11. Now tap on the Menu button (left soft key on your phone) and select  Back  from the menu. (To go back, do not press the Back button of your device.) When you do this, you should see the following lines on the screen:
    SHA256_OFF => Not Change
  12. Ignore the above message and tap on the Menu button again and then select Back.
  13. Now you’ll see the Network Lock menu. Press the Menu button again and select Back. Repeat the Menu> Back action till you return back to the UMTS Main Menu.
  14. Here you will find an option called [6] COMMON. Tap on it.galaxy-s4-service-menu-6
  15. Next, select  [6] NV REBUILDgalaxy-s4-service-menu-7
  16. In the NV Rebuild screen will look like as shown below.
    Golden-Backup exist
    You can Restore Cal/NV


  17. Tap on [4] Restore Back-up.
  18. Doing this will freeze your T-Mobile/AT&T Galaxy S4 temporarily. The screen will turn Off , followed by the Menu and Back buttons light up and device reboot.

How to Check if My Phone is Unlocked?

If you phone is SIM locked, you will not be able to use any other SIM card from other network provider. When you insert a different SIM, you’ll see a dialog pops up on your phone asking you to enter the unlock code. On the contrary, if you phone has been unlocked, you’ll be able to use any other SIM card on it. So, the best way to check or verify the unlock is to insert an unauthorized SIM card.

Try the method and let us know how it went for you. Cheers and keep visiting!

Whether the SIM-Unlocking method works or not for you, please let us know and also mention your phone’s model and if possible firmware version.

Other Interesting Stuff for Galaxy S4:

How to Speed Up Your Galaxy S4 without Rooting

How to Unroot Galaxy S4 and Reclaim Warranty

How to Root Your Samsung Galaxy S4 (All Models)

Download Full HD Wallpapers for Galaxy S4

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