If you are not in India, chances are that you might have got your phone network locked.
You Will Need:
Your Phone to be Rooted
ADB which comes with Android SDK and can be found HERE.
Latest Java SDK if you already don’t have it.
Once you have downloaded the Android SDK, run the installer trough all the steps to install it, it is recommended to install it in “C:” drive so that you can follow the tutorial as it is.
1-Go to the “Available Packages”.
2-Click on the “Refresh” Button and the bottom Right and wait until it finish
3-From Items select the “Andoid SDK platform-tools, revision x(7 at the moment)”
4-Click the “Install Selected” button.
5-Now you can either close the SDK or leave it open.
Now that you installed the SDK and the ADB its time to set the Path so the cmd.exe recognizes the ADB, there are two methods, One With cmd.exe (console) and one with the My PC Properties.
Cmd.exe (console) Method.
Click on your start button and select “Run” from the Start Menu, type cmd.exe on the box and press enter.
Once the CMD its open write the next Text: set PATH=%PATH%;C:\android\android-sdk-windows\platform-tools
The text Write in Bold means your SDK Installation Directory.
My PC Properties Method.
Open My PC, and Right click on a blank space,
Select “Properties” from the just opened context menu,
On My PC Properties select the “Advanced Options” Tab
On the “Advanced Options” tab click on the “Environment Variables” button.
Now Mark the “Path” Variable and click the “Edit” Button.
At the end of the line add this text:
Remember that The text Write in Bold means your SDK Installation Directory.
Now you have completly installed the android SDK and the ADB (Android Debugging Bridge), So here we go with the tutorial.
1. Connect your SGA to your computer via the included USB Cable. (the drivers should be installed by now, Kies installs them automatically, do not open Samsung Kies.)
2. Open cmd.exe
3. Type: cd C:\android\android-sdk-windows\platform-tools (A $ sign shall pop up)
4. Type: adb shell (From now on, after each step, a # sign shall pop up)
5. Type: su (This gives root premission to adb shell)
6. Type: cd / (Another # shall pop up)
Note- There is a space in between cd & /.
7. Type : mount -o remount rw /
8. Type: mkdir /efs
9. Type: mount -o nosuid,ro,nodev -t vfat /dev/block/stl5 /efs
10. And now type: cat /efs/mits/perso.txt
And you will get some strange characters on the screen and your unique 8 digit unlock code, make a note of it.
11. And finally type: umount /efs
12 . Disconnect your phone from your computer, turn off your Phone and insert a SIM from another company, it will ask for the Unlock Code, just type the code that you just get and you are done, your phone is now unlocked.
Now you can check that your cellphone is unlocked by typing the next code on your numeric keyboard, like if you where doing a call: *#7465625#
Credit goes to Jc_master @ XDA.
The only way to do brick your phone while doing this is by skiping the last step, umount /efs.
In case you brick your phone, no need to worry. Just download a ROM & follow this tutorial to unbrick your phone: This is The Tutorial
Do a wipe of the cache and dalvik & restart.