If you are one of those who bought Samsung Galaxy S II and now you are facing problems with changing your SIM card then this article is for you.So all those who have been waiting to unlock their Galaxy S II XDA-developers have managed to come up with the Galaxy S II SIM Unlocker that can let you free your phone locked state to allow you to use any SIM card you want in the phone.
The app is very simple to use,simply install the app, hit the “SIM unlock code” button, wait a few minutes, and it should come up with the code. It can indeed take a while, so plug your phone in the charger before running.
The app exploits the Samsung’s habit of storing SIM unlock codes in the firmware.So what the app does is that it searches your phone for its SIM unlock code. Then all you need to do is to note it down and then place the SIM card you would like to use in the phone,simply enter the unlock code when asked for.However like with most of the third-party apps trying to give you full control of your device this one also requires Rooting your device prior to its use.
Read out this post about Rooting Your Android device before you decide to Root it :