FREE Network Unlock for Samsung Galaxy S, S2 II ,S3 III,Galaxy Tab, Galaxy Note and their Variants
1. Root your GS2, S3… etc.
2. Go to market and search for “Galaxy S Unlock”, the author is “Helroz”.
(Market URL: play.google.com/store/apps/details?id=com.helroz.galaxysunlock)
3. Run the app from step 2. Go to “Unlock SGSII” tab on the top of the screen.
4. Tap on the first item:”Step 1 Backup files….”
5. Tap on the second item:”Step 2 Change lock-bytes”, and wait until your phone restarts.
6.Now, your phone is sim unlocked after the reboot
*** Tested by me: Galaxy s2 (I777 at&t)