For those of you who upgraded to iOS 6.1.6 but forgot to save the SHSH file for it, you’ll not be able to untethered jailbreak the device and unlock your iPhone. Therefore, you can only be running on 4.1 or 6.1.6 only. Currently, there are no tools to create an iOS 6.1.6 Custom Firmware. So if you want to update to 6.1.6 then just restore the original firmware using iTunes.
What is the benefit of unlocking an iPhone? You can start using a sim card from any cell phone carrier right away once your iPhone is unlocked. This is extremely helpful for those that have to travel to a different country or just want to use a different carrier than their original one.
How to Unlock iPhone 3GS on iOS 6.1.6 using Redsn0w
Step 1: Download Redsnow 0.9.15b3 and unzip it
Step 2: Once the software is launched, click on the “Extras” button
Step 3: Download iOS 6.1.6 and click Select IPSW > Choose the firmware > Click Yes (if your device is 3gs oldboot, then click No).
Step 4: Now go back to the main menu, select “Jailbreak” > give a check on install cydia and Install iPad baseband (the purpose is to get Baseband 6.15) > Next.
Note: When selecting Install iPad baseband, Redsn0w will ask you a Yes or No question, just select Yes.
Step 5: Turn off the device, put it into DFU mode and wait for the jailbreak process to be completed. If you still not see the Cydia icon on your Springboard, make sure to do a quick “Just boot”.
Step 5: Now go to Cydia and let it reload data and upgrade everything, then go ahead and install a utility called ultrasn0w.
Step 6: Still on the same Redsn0w, choose Extras > Select IPSW > click on the original iOS 6.0 firmware > Click No
Step 7: Repeat step 4 and 5, then you’re done. You have successfully downgrade from Baseband 6.15 to 5.13. Enjoy!
Did you know that you can also use a Cydia tweak called UltraSn0w to unlock the phone? We will also include a guide on that below.
How to Unlock iPhone 3GS with UltraSn0w
- Jailbreak your iPhone, obviously
- Open up Cydia and wait for it to reload
- Search for UltraSn0w and Install it
- If you can’t find the tweak, add the following repo: repo666.ultrasn0w.com
Now restart your iPhone and that’s it! Enjoy your new unlocked smartphone.