It seems a lot of people are confused if they can update their iPhone 3GS on baseband 6.15.00 to iOS 4.2.1 and then Untethered Jailbreak it using GreenPois0n. Well it is possible and with GreenPois0n for windows its even easier. All you have to do is update your iPhone 3GS and then jailbreak it. Here is a step by step procedure for you guys…
So let’s get to it and I’ll show you how to Untether Jailbreak your iPhone 3GS on iOS 4.2.1 using GreenPois0n RC5 for Windows.
Word of Wisdom
- If you are on an unlocked iPhone 3GS, DO NOT TRY THIS. Updating to iOS 4.2.1 will change your baseband. Although you can still unlock it by using the iPad baseband option but that would be “your call”.
- If you don’t have your SHSH saved for iOS 4.1, DO NOT TRY THIS. If anything goes wrong you wont be able to go back to iOS 4.1 and you’ll have to live with iOS 4.2.1.
How to Jailbreak iOS 4.2.1 on iPhone 3GS baseband 6.15
[ Step 1 ]
Download GreenPois0n for Windows [Mirror]
[ Step 2 ]
Connect your iPhone 3GS with iTunes, make sure you have latest iTunes version. Once connected hit the update button while holding shift (Shift + Update). Remember, you are not supposed to restore your device use Update option.
iTunes popup will ask for iOS 4.2.1 file for you iPhone 3GS. Give it the file according to your device and proceed. [ Download iOS 4.2.1 for iPhone 3GS ]
[ Step 3 ]
You will be greeted with a error 1013 message, its normal, Press ok for the error. Now Download TinyUmbrella for Windows and install, run it. From TinyUmbrella screen hit the “Exit Recovery” button and your iPhone 3GS should reboot. You will probably end up in Emergency Call screen and connect to iTunes screen. Turn your Device off at this point and run Greenpois0n.
[ Step 4 ]
You will be asked to put your device in DFU mode, follow the procedure on your screens.
[ Step 5 ]
Once GreenPois0n for Windows recognizes your DFU mode it will start the Untethered Jailbreak process. So just give it a minute and do not do anything here.
[ Step 6 ]
When its done you device should boot up and you’ll be able to see “Loader icon” on your homescreen.
[ Step 7 ]
Tap on Loader icon to open and from the list choose Install Cydia. That’s it you can now enjoy an Untethered Jailbreak on your 3GS running iOS 4.2.1. If you are having trouble loading Cydia or the “Loader app” run redsn0w and give it iOS 4.2.1 and from the options choose Install Cydia and uncheck the rest and continue. Your device will reboot and you’ll be able to see Cydia.
[ Unlock iPhone 3GS ]
Once you have Cydia installed tap on it and update it with all the essential updates and go to search tab and type in “Ultrasn0w” Install it to Unlock iPhone 3GS.
That’s it, you are now on iOS 4.2.1 fully untethered and you are unlocked on your same baseband 6.15.00. Here is a complete guide if you are having trouble, this covers all errors and bugs of Greenpois0n. I am on Twitter and Facebook if you need any help.