iPhone 3G JailbreakingPhoto credit: patrick h. lauke (Flickr)

WARNING: If you rely upon a carrier unlock (sim unlock) to be able to use your iPhone 3G please DO NOT follow this guide.  Updating to iOS4 in the detailed manner will upgrade your iPhone’s baseband permanently.  The jailbreak team may release a sim unlock for the new baseband at a later date; however there is also every chance they won’t too!

FURTHER WARNING: Whilst the process we’re going to detail is simple the jailbreak step is recommended only for developers / confident users since the jailbreak method is in a beta state.

LAST WARNING: You can only complete this process if you have either an active sim card for the network that your iPhone should be on, or have a factory unlocked iPhone since the iPhone will need to activate itself via iTunes.

A REMINDER: This process is for the iPhone 3G only.  Separate articles will exist for the 3GS at a later date.

Getting Started

I recommend you read this guide in full, then read it again before you even think about getting started.  I don’t mean to sound condescending; however this is the advice given on even the community pages of the jailbreak team, so it’s worth repeating here.

Whilst the process is proven and widely used, there is almost an element of risk involved.  You undertake the detailed process at your own risk.  Feel free to ask questions in the comments section and we’ll aim to help wherever we can.


Download and install iTunes 9.2

Download iPhone 3G iOS4

UPDATE: Links removed – iOS4 is now available from iTunes; just tell your iPhone to update to the latest version

NOTE: If you decide to jailreak (next section point redsn0w at the downloaded IPSW file.  This can be found in the following location:

On Windows:
Documents and Settings\<User>\Application Data\Apple Computer\iTunes\iPhone Software Updates

On Mac:
~/Library/iTunes/iPhone Software Updates

Upgrade to iOS4

  1. Connect your iPhone to computer and perform a full backup (if necessary, right click your iPhone in iTunes and select backup)
  2. Copy any photos stored on your iPhone to your computer (I accidentally lost mine when updating so it’s best to be safe than sorry!)
  3. Once you’ve verified your backup and ensured you’ve got all your data safe, click on your iPhone in iTunes so the main screen displays options to restore.
  4. Windows users should hold down the shift key and right click the “restore” button.  Mac users should hold down the ctrl and shift keys whilst clicking the “restore” button.
  5. Browse to the IPSW file you downloaded in the pre-requisites section
  6. Once you’ve confirmed your choice you’ll need to sit back and wait about 10 minutes.  Your iPhone will reboot and install the new iOS4 software.
  7. Once the install is successful, iTunes will detect the updated iPhone and ask if you wish to set it up as a new device, or if you’d prefer to restore your settings / data from the backup you made in step 1.  The choice is yours – I personally restored my settings since I didn’t want to have to setup all my email, contacts, wifi access points etc again.

NOTE: After my iPhone had completed its install of iOS4 my iPhone hung on a screen asking to be connected to iTunes and iTunes didn’t automatically pick the iPhone wanted to chat.  The easiest way to overcome such a situation (should it occur for you) is to unplug the iPhone, reboot your computer, open iTunes and reconnect your iPhone.

NOTE 2: If you intend to jailbreak your handset, then I would recommend holding off on spending the time restoring your data until the jailbreak is complete just in case you need to restore and start over again.  It’s unlikely, but I like to be cautious.

Jailbreaking your handset

NOTE: You do not have to jailbreak your handset unless you want to.  If you wish to keep a your iPhone on the vanilla version of iOS4 you can stop now and enjoy the fruits of your labour.  What you’ve installed is what Apple will widely release at a later date via their official channels – you’ve just got it early!  I would just mention that Apple don’t want you to use wallpapers or multi-tasking in the iOS4 release for iPhone 3G.  Even if you jailbreak your handset and do nothing more beyond the initial jailbreak, you can enjoy both of these features on your iPhone 3G!  If you do want to jailbreak then please read on….

It is important to note that at the time of writing this guide the iOS4 update was not widely available.  Many of the applications available on the Cydia/Rock platforms are/were not updated to be able to work on the iOS4 platform and therefore it is imperative that before you attempt to install any jailbreak app that you check it is compatible with iOS4.  Failure to do so and the installation of an incompatible application can result in crashing your iPhone, and in most cases will need a full restore of the iOS platform to recover from.  There’s a spreadsheet detailing compatibility of some apps here.

Jailbreak process

Get the version of redsn0w as appropriate for your computer operating system:

Download Redsn0w 0.9.5 for Windows
Download Redsn0w 0.9.5 for Mac

Extract the contents of the archive to your desktop or other favoured place.

Are you ready?  Let’s begin….

  1. Connect your iPhone to your computer
  2. Close iTunes (if already open or if it opens when iTunes opens)
  3. Power off your iPhone by holding the power button and using the “slide to power off”
  4. Open the redsn0w application and follow the on-screen instructions, typically:
  5. Browse to the IPSW file (details above of where this is located)
  6. Choose whether or not you want wallpaper/multi-tasking enabled on your device (active by default)
  7. Confirm choice and proceed to jailbreak (requires DFU mode)
  8. You have to be on the ball to put your iPhone into DFU mode, it’ll prompt on screen however it’ll involve the following:
  9. Press and hold power button for 5 seconds
  10. Keep your finger on the power button but press and hold the home button too
  11. When prompted (roughly 10 seconds) release the power button but keep the home button pressed
  12. When the device drops into DFU mode redsn0w will change on screen and start to jailbreak the handset.  Hands off the computer and walk away til it’s done (or watch the iPhone)

Once the jailbreak completes your iPhone will reboot.  You aren’t done yet since in this early beta of the jailbreak we need to update Cydia so that you can actually use it.

  1. Open Cydia (a white icon at the moment)
  2. Allow it to refresh itself, after which it will close
  3. Open Cydia again (should be a nice familiar Cydia icon now)
  4. When prompted, install the essential updates only
  5. If necessary, Cydia will close or require a reboot
  6. Open Cydia again, install any remaining updates

You are now in a position to be able to install apps.  Like I said earlier, lots just aren’t ready yet so you should be cautious and check compatibility first.  For example, to install SBSettings, you need to currently add the following repository to your Cydia list: thebigboss.org/betarepo/

Personally, that’s all I’ve installed.  There are many others I’d like to install (see my recommended list); however I realise I’ve got to be patient.  At least I can enjoy iOS4 ahead of time and it’s new features safe in the knowledge that as jailbreak apps are updated, I can add them.

Questions and comments

Please ask them in the comments section below.  I’ll endeavour to answer them as clearly as possible.

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Be sure to check back soon for updated guides and info.

Update: 22/06/10

iOS4 got released last night officially.  I’ve therefore removed the links from the article above and suggest you use iTunes to grab the IPSW file.  Furthermore, the previously posted redsn0w links have been replaced with links to a new version since the ones we pointed to worked with the developer GM version of iOS4, they don’t with the version Apple released yesterday.


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