How to unlock iPhone 3GS on iOS 5.1 baseband (modem firmware) 5.16.05?
UPDATE: You can now unlock it for free, follow the steps here.
The untethered jailbreak for iOS 5.1 is not yet available and baseband 5.16.05 can’t be unlocked.
If you really need to unlock your iPhone 3GS it’s still possible to do it by updating the baseband to 6.15.00. Take note of the following:
- Baseband 6.15.00 is an iPad baseband which can break your GPS.
- More risks here.
- If you have the new iPhone 3GS 8GB made after week 28 of 2011, you must read this first or else you will permanently break your iPhone.
Note: Baseband can never be downgraded even if you can downgrade your iOS!
[Final warning: Proceed at your own risks!]
1. Backup your contacts, photos, apps etc. Remove any SIM card.
2. Download iOS 4.1 firmware for iPhone 3GS.
4. Download latest version of TinyUmbrella from here.
6. Put your iPhone into DFU mode. See YouTube video here.
7. 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. If you get an iTunes error 3194, read here on how to fix it.
8. The restore will end with error 1015 and recovery loop on the iPhone, this can be resolved using the “Exit Recovery” button in TinyUmbrella.
9. Start redsn0w 0.9.6rc18.
10. Browse for the iOS 4.1 firmware you just downloaded.
11. Select ‘Install Cydia’ and ‘Install iPad Baseband’. Warning: installing iPad baseband will break your GPS.
12. Follow on screen instructions to put your device into DFU mode to begin the jailbreak.
13. When the process is done, you will find that your iPhone is now jailbroken on iOS 4.1 with iPad baseband 6.15.00. To make sure you can always go back to iOS 4.1, launch Cydia and select ‘Make my life easier.’
If you’re happy with iOS 4.1 and would like to unlock it, skip to step 19 now.
Step 14 to 18 is only possible if you have your SHSH saved. What is SHSH?
Let’s restore it to iOS 5.0.1 to get untethered jailbreak and then unlock it with ultrasn0w 1.2.5.
15. Download the latest redsn0w from the Dev Team’s website or from here. Start redsn0w, go to Extras > Pwned DFU. This allows your iPhone to accept custom firmware.
16. Reinstall iTunes 10.5.
17. Connect your iPhone to your computer and hold shift+restore (Windows) or option+restore (Mac) and select the custom iOS 5.0.1 IPSW you just downloaded. If you get an iTunes error 3194, read here on how to fix it.
18. Once the restore is done, your iPhone will now have iOS 5.0.1 with baseband 6.15.00. If you are stuck on Apple logo with an empty loading bar, run redsn0w again but this time click on Extras then Just Boot.
19. Launch Cydia from Springboard (home menu).
20. Search for ultrasn0w on Packages in Cydia. If you cannot find it, add new sources by typing ultrasn0w repo:
repo666.ultrasn0w.com (with zero, not o).
21. Install Ultrasnow 1.2.5.
22. Reboot your iPhone. Just in case it’s stuck on Apple logo, run redsn0w again, go to Extras > Just Boot. Follow on screen instructions.
23. Turn off 3G and insert your SIM card. It should pick up your carrier signal.
If you follow the exact instructions this will work 99%.
Good luck and leave your comments or questions below.