How To

How To: Unlock a Samsung Galaxy S2 For Use on T-Mobile/AT&T

May 25, 2011 at 11:55 am

Galaxy S II Unlocker

One of the year’s most anticipated phones, the Samsung Galaxy S II, has yet to make its US debut, but if you want to impress all your friends and order one from the UK ahead of time, we’ll show you how you can use it on AT&T or T-Mobile.  Overseas phones use GSM Technology, just as AT&T and T-Mobile do, and even though the bands are slightly different here that won’t stop you from using an overseas phone on them.  Let’s dive in.


This process requires the device to be rooted, which can cause damage to your device if not done properly. is not responsible for any damage you may do to your device!  In addition, since bands are different in the US you may only get Edge data networks.

Before you begin:

Root your device.  Instructions for rooting a Samsung Galaxy S II can be found at the XDA Forums.  This process requires a couple of file downloads, so make sure to follow that source link as the information is fresh and may change.

Step-by-step Guide

Once you have rooted your device, you’re ready to go.

  • The next step is to visit the Android Market and download the application “Galaxy SII Sim Unlock“.  This application was created solely for this purpose by Odia of the XDA Forums.
  • Install and run the app.
  • Hit the “SIM Unlock Code” button and write it down. This could take a couple of minutes.

SIM Unlock

SIM Unlock

  • Shut down your phone.
  • Place the new carrier SIM card in your device and start it up.
  • When the code is requested, enter it.

If the code does not take, the developer warns not to try it again, as it could freeze your device.  The app is also able to give you an unfreeze code, though.  It may report that the lock was unsuccessful, but upon reboot it might have worked, so go ahead and give it a try.  Best of luck!

Source XDA

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