Jailbreaking/unlocking the 3G iPhone on 4.2.1 firmware using redsn0w/ultrasn0w
Updated: February 3, 2011
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Who is this guide for?
I used iTunes 10.1.2.
I used OS X 10.6.6.
Thanks again go out to the iPhone Dev Team for providing this amazing, and FREE program for
customizing the iPhone. You can visit their website here,
and their blog here.
You can read their
notes regarding 4.2.1 firmware here.
Answer this question: What modem firmware (baseband) is currently on your iPhone? Launch the
Settings program, press General, then press About and scroll down to the bottom of the screen.
If your version is 5.13.04 or lower
you'll want to preserve that unlockable baseband by
using the PwnageTool program to create a custom restore file. The current version of PwnageTool
contains a bundle for 4.2.1 firmware which should allow you to create a custom 4.2.1 firmware. I
do not have the ability to test this as I used redsn0w. I do not have a tutorial that will cover
You can look at previous PwnageTool tutorials of mine to figure out how to do this;
it's basically the same process. I think you'll then have to use redsn0w to jailbreak the iPhone
once you have restored with this custom firmware. At least that is the process with the 3G S.
If your version is 5.14.02 or higher
there is no unlock for this modem firmware and you'll
have to install iPad modem firmware to unlock. There are several pit falls to doing this which
will be pointed out in Step 2.
My iPhone 3G already had 5.14.02 modem firmware and couldn't be unlocked anyway, that's why I
went down the path in this tutorial. If I had an unlockable modem firmware I would have written
an PwnageTool tutorial instead.
There are some serious consequences to updating the iPhone's modem firmware to a version used by
the iPad. But if you want to be unlocked, then this is the only way currently
to do this.
- Your modem firmware will be upgraded to version 06.15.00. There is no way to hide the fact
that this version will be on your iPhone. Should you need warranty assistance from Apple/AT&T
you will have voided your warranty by installing this modem firmware version.
- There is no way to downgrade this iPad modem firmware once installed.
- If an iPhone modem firmware is released and it is newer than version 5.15.04, you will not be
able to install it unless it is higher than version 06.15.00.
- Beginning with firmware 4.2.1, if you have modem firmware 06.15.00 installed you will not be
able to restore to stock firmware (it will fail). You can either restore to older firmware (that
you have SHSHs for) or resinstall a custom version of 4.2.1 firmware.
- iPad modem firmware 06.15.00 renders GPS functionality useless when installed on an iPhone 3G.
Plan on losing this feature if you proceed with this tutorial.
Using iTunes, restore to 4.2.1 firmware.
Download redsn0w version 0.96b6 from the iPhone Dev Team
Download iOS firmware 4.2.1 for the iPhone 3G here:
If your downloaded file ends in .zip, rename it to end in .ipsw. Note: Safari likes to open "safe"
files by default. You must turn this feature off for this download to work correctly. Click
"Safari", select "Preferences", from the "Geneal" tab uncheck the box that says "Open "safe" files
after downloading". Otherwise just use Firefox to download this firmware file.
You should now have these two icons on your desktop.
Double click the redsn0w file and it will place a folder on your desktop. Go into this folder and
place the redsnow.app file into your Applications folder on your computer. Overwrite any previous
Launch redsn0w. Cick the Browse button.
Navigate to your 4.2.1 firmware file, select it and click Open.
The file will be identified. Click Next.
A pop up window will appear.
Redsn0w will present a myriad of options.
- Install Cydia is for adding the Cydia program to gain access to the jailbreak community of
- Install custom bundle is for adding your own .tgz or .tar.gz files to the jailbreak. When
you select this a file browser window will open.
- Install iPad baseband is for unlocking the iPhone if your modem version is currently 5.14.02 or
higher. When you select this a warning screen will appear.
- Verbose boot lets you see code scroll on the iPhone when booting.
- Custom boot logo is for adding your own graphic in place of the Apple graphic on boot up. When
you select this a file browser window will open.
- Custom recovery logo is for adding your own graphic in place of the connect to iTunes graphic.
When you select this a file browser window will open.
- Enable multitasking is for you to experiment with. Personslly I think the 3G is a dog as it is
on 4.x firmware let alone enabling this barrel full of monkeys.
- Enable homescreen wallpaper will allow you to easily change your wallpaper on your various
pages without having to use WinterBoard.
- Enable battery percentage will replace the battery graphic (the small one) with a numeric value.
- Deactivate is for those of you that want to use the Subscriber Artificial Module (SAM) program
on Cydia. This program (SAM), creates authentic activation tickets for the iPhone so that PUSH will
function correctly. SAM also has the side benefit of solving an issue where battery life is
decreased by those who do not have an authorized SIM card to activate with, and use ultrasn0w to
unlock with. The deactivate option works by replacing the modified lockdownd file (created during
the jailbreaking process) with a stock version. To make this work: jailbreak without checking
deactivate, install ultrasn0w, install SAM, run redsn0w again and then check the deactivate box,
then reboot. You can learn more about SAM
- Just boot tethered right now - is for those that are already jailbroken via a tethered method
and need only reboot, not jailbreak all over again.
- Just enter pwned DFU mode right now - walks you through DFU mode used for restoring purposes.
My selections were install Cydia and iPad baseband. Here's the pop up message you'll receive.
When you've made your choice at the pop up click Next in the options screen.
Make sure your iPhone is turned off and plugged in via USB. Click Next.
Instructions for entering DFU mode will appear. They start right away and go very quickly so try to
keep up! First hold down the Power (sleep/wake) button for three seconds.
Keep holding on to the Power button, and press and hold the Home button for 10 seconds.
Continue holding the Home button, and release the Power button.
Redsn0w will display various messages.
You'll see a graphic that says jailbreak data is being downloaded on the iPhone.
Done will appear in the program.
Scrolling code will appear on the iPhone.
You will see a few different messages (Installing base utilities, Replacing kernel, Flashing NOR,
Flashing Baseband, Installing bundles, Activating, Syncing file systems, Moving Applications,
Rebooting) on your iPhone during the next couple minutes. The iPhone will reboot once this has
Launch Cydia. You'll see the message intializing the file system.
Launch Cydia again and make your selection at this screen. Press done. Press Upgrade Essential.
Press Continue Queuing. Press Search.
Enter ultrasn. Press it when it appears on the screen. Press Install.
Press Confirm. Press Reboot Device.
The iPhone will reboot. Here is my about screen showing that I'm on T-Mobile, on 4.2.1 firmware
and on iPad baseband 06.15.00. Note: I blur out many values on this screen as it is personal
Page 2 will cover how to create a custom firmware file with PwnageTool or use TinyUmbrella to
restore your iPhone should you need to.