For those of you with a GSM Galaxy Note 2 (such as AT&T Galaxy Note 2 SGH-i317, T-Mobile Galaxy Note 2 SGH-T999, or any Note 2 that has a SIM slot but SIM is locked to specific carrier), there’s an easy, “free” way to unlock the SIM so you can use another SIM card from another carrier or perhaps you want to unlock SIM so you can use your phone while traveling internationally.
Well, I had the pleasure of using both my AT&T and T-Mobile Galaxy Note 2 in South Korea where I am currently staying, with voice/3G/4G HSPA+ working flawlessly.
This also does work on GSM Galaxy S3s also by the way and rooting isn’t required!
Step 1. Insert a SIM on your Note 2, you should find the familiar “SIM network unlock PIN” window.
Step 2. Dial “*#197328640#” on your Note 2 to enter special menus.
Step 3. Choose “UMTS”.
Step 4. Next choose “Debug screen”.
Step 5. Choose “Phone Control”.
Step 6. Choose “Network Lock”.
Step 7. Choose “Perso SHA256 OFF” and wait about 30 seconds.
Step 8. Press the Menu button then choose “Back”.
Step 9. Choose “NW Lock NV Data Initiallize” and wait about 1 minute. Then reboot your Note 2.
Step 10. Once rebooted, you should no longer get the Network Lock window anymore and you should be able to get signal and data. If you have trouble getting 3G/HSPA+ data, try setting the APN to your carrier’s settings although it should set automatically.
If you are on Android 4.1.2, try installing Phone Utility to access the menus or reflash Android 4.1.1 ROM to unlock (then revert back to 4.1.2 once unlocked)