How To Unlock iPhone 3GS On iOS 5 Baseband 05.16.05 [Guide]

But there’s is solution, if you’re stuck on iOS 5 with baseband 5.16.05 and lost your unlock this guide will help you not only to unlock your iPhone 3GS on baseband 05.16.05 but also upgrade back to iOS 5 with your baseband preserved. Luckily Apple is still signing iOS 4.1 for iPhone 3GS and 3G which means you can downgrade your iPhone 3GS to iOS 4.1 and baseband 5.14.xx or 5.15.xx.
Couple of things you should know before proceeding: 

• This process involves flashing iPad’s baseband 6.15.00.
• If you want to upgrade to iOS 5 then you should know that there’s no untethered jailbreak for iOS 5 available right now.
• If you flash iPad baseband 6.15.00 on your iPhone 3GS you won’t be able to update your iPhone 3GS firmware normally from iTunes, you will have to cook a custom firmware file using redsn0w or sn0wbreeze and then update your iPhone 3GS.

If everything’s ok and you still want to unlock your iPhone 3GS on iOS 5 baseband 5.16.05 follow this guide.

How To Unlock iPhone 3GS on iOS 5 With Baseband 5.16.05:

Things you will be needing during this process: 
iOS 4.1 for iPhone 3GS download it from here
iTunes 10.4.1 download it from here (Windows (32Bit) | Mac)
redsn0w 0.9.8rc18 download it for (Windows | Mac)
Pre-jailbroken hacktivated iOS 5 for iPhone 3GS download it from links below:

• iPhone 3GS iOS 5.0 Jailbroken (New Bootrom)
• iPhone 3GS iOS 5.0 Untethered Jailbroken (Old Bootrom)

iTunes 10.5 download it from here
Redsn0w 0.9.9b6 download it from here
Step1: First of all make a backup of your contacts and data on your iPhone 3GS.
Step 2: Remove SIM card from your iPhone 3GS
Step 3: Uninstall iTunes 10.5 Completely from your computer and install iTunes 10.4.1. (Download link given above)
Step 4: Put your iPhone in DFU mode, you can enter DFU mode by following these step:

• Hold down both the Home button and the Power button for 10 seconds.
• Release the Power button and continue holding the Home button until (approx 15-25 sec) your device’s screen turn black.

Step 5: Launch iTunes, connect your iPhone, hold down the SHIFT for Windows or Option for Mac while you click the RESTORE button in iTunes and select the iOS 4.1 firmware file you have just downloaded.
Step 6: The restore process will end with error 1015 and recovery loop on your iPhone, this can be resolved using the “Exit Recovery” button in TinyUmbrella. (Download TinyUmbrella from here)
Step 7: Start redsn0w 0.9.6rc18 and browse for the iOS 4.1 firmware you just downloaded.

Step 8: Select “Install Cydia” and “Install iPad Baseband” and click “Next”
Warning: DO NOT UNPLUG your iPhone or interpret this process. 
Step 9: Follow the instructions on screen and put your iPhone 3GS in DFU mode.
Step 10: After this redsn0w run your iPhone 3GS will be successfully jailbroken on iOS 4.1 with iPad’s baseband 6.15.00.
Open Cydia and tap on “Make my life easier”, this will save your SHSH blobs on Cydia servers for future downgrades to iOS 4.1. (Recommended)
Note: If you don’t want to update your iPhone 3GS with iOS 5 then skip to Step 16.
Let’s install iOS 5 on your iPhone 3GS with your baseband preserved.
Step 11: Uninstall iTunes 10.4.1 and install iTunes 10.5 (download link mentioned above).
Step 12: Run redsn0w 0.9.9 b6, click Extras and then click Pwned DFU


Step 13: Follow the instruction on your screen to put your iPhone 3GS in Pwned DFU mode.
Step 14: Launch iTunes 10.5, hold down the SHIFT for Windows or Option for Mac while you click the RESTORE button in iTunes and select the iOS 5.0 firmware file you downloaded from links above.
Step 15: After restoration process your iPhone 3GS will be kicking iOS 5 with baseband 6.15.00.
Step 16: Follow our complete step by step guide posted here to unlock your iPhone 3GS on iOS 5 BB 06.15.00 using ultrasn0w 1.2.4.
And that was it guys, remember if you face any problems or errors you can always contact us on our Facebook page or ask us on Twitter.
We will keep you updated on this, stay tuned!
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