21-08-2011, 03:29 PM
How to Jailbreak an iPhone 3G on 4.2.1 using RedSn0w for Windows
There are two terms that are commonly referred to, they are Jailbreak and Unlock.
Jailbreaking is when you remove limitations that Apple have set through the use of custom kernels. Jailbreaking allows you to gain root access to your device and install software that Apple hasn't approved through apps / installers such as Cydia.
Unlocking is updating your baseband so that you can use any network / sim card eg. tmobile OR orange OR vodafone. I have updated my baseband but it's not covered in this tutorial.
Steps
These are step by step instructions on how to jailbreak your iPhone 3G on the 4.2.1 firmware using RedSn0w for Windows.
1) Download RedSn0w here and download the 4.2.1 firmware from here
Alternatively, I've mirrored the downloads and placed them both in a zip file on my site here
Once downloaded, extract the files.
![[Image: 4.2.1-jailbreak-01.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-01.png)
2) Connect your iPhone to your computer and launch iTunes.
Select your iPhone from the list of devices on the left. Now hold down Shift on your keyboard and click the Restore button.
Navigate to the folder where you saved the files and select the 4.2.1 firmware ipsw.
![[Image: 4.2.1-jailbreak-02.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-02.png)
3) Once iTunes has finished updating your iPhone to the desired firmware launch the redsn0w application from the folder we extracted earlier. (Run it as Administrator in Vista / Windows 7)
4) Once RedSn0w opens click the Browse button
![[Image: 4.2.1-jailbreak-03.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-03.png)
5) Select the 4.2.1 firmware ipsw and click Open.
![[Image: 4.2.1-jailbreak-04.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-04.png)
6) Once the firmware has been verified click the Next button to continue.
![[Image: 4.2.1-jailbreak-05.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-05.png)
7) RedSn0w will now prepare the jailbreak data.
![[Image: 4.2.1-jailbreak-06.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-06.png)
8) From this window, select the options that you want. (Keep Cydia ticked)
![[Image: 4.2.1-jailbreak-07.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-07.png)
Verbose boot displays detailed information on boot of your device and is generally only needed by developers and advanced users.
If you want to use a boot image, they have to be a RGB or Grayscale format with Alpha channel and dimensions below 320x480.
Click the Next button to continue
9) Plug your iPhone into your computer and make sure it's powered OFF then click the Next button
![[Image: 4.2.1-jailbreak-08.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-08.png)
10) RedSn0w will now guide you through the steps to get into DFU mode. (Just follow the onscreen prompt)
![[Image: 4.2.1-jailbreak-09.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-09.png)
11) RedSn0w will then begin uploading the new RAM Disk and Kernel.
![[Image: 4.2.1-jailbreak-10.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-10.png)
12) Once this is complete you will be notified that RedSn0w is done. Click the Finish button.
When your iPhone finishes rebooting (5 minutes or so) it will be jailbroken with Cydia on the SpringBoard.
![[Image: 4.2.1-jailbreak-11.png]](http://markwood.co.cc/donotdelete/4.2.1-jailbreak/4.2.1-jailbreak-11.png)
Credits
Thanks to iclarified, (most of this thread is from here)
Thanks to the iPhone Dev-Team, find them here
Thanks to the community over on modmyi, find them here
There are two terms that are commonly referred to, they are Jailbreak and Unlock.
Jailbreaking is when you remove limitations that Apple have set through the use of custom kernels. Jailbreaking allows you to gain root access to your device and install software that Apple hasn't approved through apps / installers such as Cydia.
Unlocking is updating your baseband so that you can use any network / sim card eg. tmobile OR orange OR vodafone. I have updated my baseband but it's not covered in this tutorial.
Steps
These are step by step instructions on how to jailbreak your iPhone 3G on the 4.2.1 firmware using RedSn0w for Windows.
1) Download RedSn0w here and download the 4.2.1 firmware from here
Alternatively, I've mirrored the downloads and placed them both in a zip file on my site here
Once downloaded, extract the files.
2) Connect your iPhone to your computer and launch iTunes.
Select your iPhone from the list of devices on the left. Now hold down Shift on your keyboard and click the Restore button.
Navigate to the folder where you saved the files and select the 4.2.1 firmware ipsw.
3) Once iTunes has finished updating your iPhone to the desired firmware launch the redsn0w application from the folder we extracted earlier. (Run it as Administrator in Vista / Windows 7)
4) Once RedSn0w opens click the Browse button
5) Select the 4.2.1 firmware ipsw and click Open.
6) Once the firmware has been verified click the Next button to continue.
7) RedSn0w will now prepare the jailbreak data.
8) From this window, select the options that you want. (Keep Cydia ticked)
Verbose boot displays detailed information on boot of your device and is generally only needed by developers and advanced users.
If you want to use a boot image, they have to be a RGB or Grayscale format with Alpha channel and dimensions below 320x480.
Click the Next button to continue
9) Plug your iPhone into your computer and make sure it's powered OFF then click the Next button
10) RedSn0w will now guide you through the steps to get into DFU mode. (Just follow the onscreen prompt)
11) RedSn0w will then begin uploading the new RAM Disk and Kernel.
12) Once this is complete you will be notified that RedSn0w is done. Click the Finish button.
When your iPhone finishes rebooting (5 minutes or so) it will be jailbroken with Cydia on the SpringBoard.
Credits
Thanks to iclarified, (most of this thread is from here)
Thanks to the iPhone Dev-Team, find them here
Thanks to the community over on modmyi, find them here
