If you use ultrasn0w or Gevey SIM to unlock your iPhone, here’s the ultimate guide to safely update to iOS 5.1.1 while preserving your baseband using the latest version of redsn0w.
UPDATE: AT&T iPhone 4 and 3GS can now be officially unlocked and many other worldwide network as well.
About a week ago, I posted a tutorial on how to build custom untethered jailbroken iOS 5.1.1 firmware using sn0wbreeze 2.9.5. Since sn0wbreeze is only available for Windows, Mac users might be a little left out. However, with the latest redsn0w that was just released a few days ago, both Windows and Mac users can now build custom iOS 5.1.1. Pwange tool is another program for Mac users to build custom firmware.
You’ve probably read the following countless times, but if you’re new to using locked iPhone, it may be worthwhile to read and understand the points below:
- Custom firmware allows you to restore your iPhone without updating the baseband.
- By preserving the baseband, you can continue unlocking your iPhone; either with ultrasn0w (supported baseband only) or Gevey SIM depending on your iPhone or baseband version.
- There’s no known software method to downgrade your baseband, once it’s updated, there’s no turning back. However, we do offer chips replacement for iPhone 4 or 3G/3GS.
- With redsn0w 0.9.12b1 (Windows or Mac), it can untethered jailbreak iOS 5.1.1.
- If you’ve downgraded your baseband chip with us, this guide will be useful for you. Under no circumstances you should restore using stock firmware.
Before you begin, always remember to backup your iPhone.
Part One: Building and Installing Custom iOS 5.1.1 Firmware (Baseband Preserved)
2. Download redsn0w 0.9.12b1 from the Dev Team’s website. It’s available for both Windows and Mac.
3. Launch redsn0w.
4. Click Extras > Custom IPSW and locate the original iOS 5.1.1 that you just downloaded in Step 1.
5. Redsn0w will identify the IPSW file:
- If you have an iPhone 3GS, it will ask whether you have a new or old bootrom. Read and choose carefully.
- If you have an iPhone 4, it will start building the custom firmware immediately.
6. Now wait until redsn0w completes the custom iOS 5.1.1 for you. Once the custom iOS 5.1.1 is ready you will find it at the same location where you stored the original firmware you downloaded in Step 1.
7. Before restoring your iPhone, you MUST put your iPhone into pwned DFU mode. This allows it to accept custom firmware. Otherwise, you’ll get an error message during restore. Redsn0w can help you do this. To pawn DFU your iPhone:
- In redsn0w > Extras > click Pwned DFU. Follow on screen instructions.
To begin restoring, be sure your iPhone is already in pwned DFU mode (black screen) then launch iTunes, press shift (Windows) or Option (Mac) on your keyboard and click restore. Select the custom firmware that was just created.
To be sure, the file name always begin with NO_BB_iPhonexxxxxxxxxx_Restore.
You can also download ready made custom firmware below (hosted on FileFactory, membership required):
- iPhone 4 custom iOS 5.1.1 jailbroken untethered with no baseband update (preserved) [download]
- iPhone 3GS custom iOS 5.1.1 jailbroken untethered with no baseband update (preserved) [download]
Part Two (a): Unlock with ultrasn0w
1.2.7 from Cydia [for supported baseband only]
1. Launch Cydia and add the following source by going to Manage > Sources > Edit > Add:
2. Install ultrasn0w 1.2.7.
3. Reboot your device.
Note: For those using iPhone 3GS with baseband 6.15.00: If you think you’ve done everything right but still getting ‘No Service’, run redsn0w > Jailbreak > Install iPad Baseband.
Part Two (b): Unlock with Gevey SIM [for iPhone 4 baseband 02.10.01, 03.10.01 or 04.10.01 only]
1. Eject your SIM tray and reboot your iPhone.
2. Once restarted, unlock your screen. Turn off 3G and cell data (you can turn these on later). Insert your SIM tray along with your SIM card and Gevey SIM.
3. Wait for Accept Screen. Tap Accept.
4. You will see No Service (in iOS 4.x, you will see one signal bar). Wait for 15-20 seconds and dial 112. Hang up after 1-2 seconds.
5. Turn on Airplane Mode and wait for ‘NO SIM CARD INSTALLED’ message. Turn off Airplane Mode and you will see ‘SIM FAILURE’ and tap OK. Your iPhone will connect to your network now.
That’s it! Your iPhone is now unlocked on iOS 5.1.1 along with untethered jailbreak.
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