Things I wish I knew before jailbreaking
It is prudent to do a lot of research before attempting to jailbreak your iPhone. I would encourage you to do it on your own. But here are some important tips to get you started, and some things I wish I knew before I went ahead and did it.
Know and trust your chosen method
There are several ways to jailbreak your iPhone. Different hackers have provided different tools for you to use, some more popular than others. By far the most popular and easiest methods are Pwnage Tool or RedSn0w (formerly QuickPwn) provided by the iPhone Dev Team. (Read key terms for explanations.) Both feature a graphical interface and a step by step approach. Before attempting, read a good online tutorial such the one at ifonenation.
Understand the risks and time involved
Jailbreaking will violate your warranty and the terms of your carrier contract. So choose a reversible method. With the Dev-Team tools, you can always restore Apple’s default firmware. Jailbreaking using restore (ie, wiping the phone clean first) is recommended over using upgrade. This is because every time you upgrade you lose a chunk of disk space taken up by your last OS installation. However, if you use the cleaner restore, you will lose all your settings and have to re-enter them. You should not allow iTunes to restore any backup (see below). You’ll probably have to re-synch all media content from iTunes. This is a time consuming process that you’ll want to allow time for to make sure your phone is in stable condition.
Be warned that there have been persistent rumors that Apple may get vindictive and deliberately brick jailbroken phones with firmware upgrades. This is all the more reason never to upgrade via iTunes.
Do not restore from an iTunes backup
After jailbreaking, don’t restore an iTunes backup. Doing so may work, but may lead to unexpected instability. It is much better to start from scratch, re-adding and even re-downloading free applications from the store, re-synching your media, and manually re-entering your settings. (Or try some semi-automated methods such as this script for OS X.)
Of Cats and Mice: official firmware upgrades and jailbroken updates
Every time Apple releases a firmware update for the iPhone, Apple uses more sophisticated (and unknown) methods to counter jailbreakers. Applying official firmware upgrades through iTunes may make it harder if not impossible to jailbreak later. Therefore, do not upgrade your iPhone through iTunes if you ever might possibly want to jailbreak it. With every firmware update, hackers have to completely re-do their jailbreaking exploit. This may take days or weeks to do, so be patient.
Really get to know your firmware version
It is vital to understand what official firmware version you’re interested in, and what version of the jailbreaking tool goes with it. This can frequently cause confusion, so read carefully. For example, Apple released firmware version 2.0.1 but the iPhone Dev Team had already released Pwnage Tool 2.0.1 to correct a problem with jailbreaking Apple firmware 2.0. So the version of Pwnage Tool that goes with Apple firmware 2.0.1 is actually Pwnage Tool 2.0.2. Confusing, but it is crucial to understand this.
Furthermore, you should make sure than any 3rd party software you install and use is compatible with each firmware upgrade.
Understand key terms and jargon
jailbreaking: to modify a device’s firmware in order to remove certain kinds of access restrictions
unlocking: to unlock the phone from its official carrier allowing you to use any SIM card. There are hardware unlocks you can buy. Successful software unlocks have been released by the Dev-Team. (See yellown0w and ultrasn0w.)
hacktivating: to activate your phone unofficially when using one of the below tools. This is necessary if you do not have an official iPhone carrier.
pwnage: geek lingo for “to own,” or perhaps more colloquially, to make something or someone one’s bitch.
Pwnage Tool: the Mac application provided by the iPhone Dev Team for jailbreaking your phone. Requires restoring phone.
QuickPwn: an alternate cross-platform jailbreaking application provided by the Dev Team. Allows you to quickly jailbreak firmware that has been upgraded by iTunes. (See understand the risks and time involved header, above, for distinction between restore & upgrade.)
RedSn0w: the replacement for QuickPwn as of FW 3.0. Also cross-platform.
blackra1n: rival jailbreak method for OS 3.1.2 (3G & 3GS) released by GeoHot. Very fast jailbreak but ‘tethered’, which means you must re-do it every time you reboot your phone. No unlock and Windows only.
jailbreakme.com: the super-easy web based jailbreak for iOS 4.0/4.01 (but not 4.02+) by comex.
Cydia: an installer tool included in the Pwnage Tool package that is like the App Store application for unofficial applications.
Installer: another tool included in the Pwnage Tool package with a similar function. Cydia is recommended currently. Be cautious of using such tools if still in beta. Discontinued as of firmware 3.0.
Icy: ditto, introduced with firmware 3.0.
Sources: On-line places to get extra software through the above tools. Some sources are included in the distribution of these tool, but others can be found on the web and added to them. Be cautious that you add only sources that you trust.
Repos: Repositories. Similar to sources. I will admit I don’t myself yet understand the distinction.
Packages: individual software products listed in sources that you can install. Some are back-end software without a GUI, and should only be installed if you know what you’re doing.
DFU Mode: The recovery mode for the iPhone which will force iTunes to ask to restore firmware. Typically you must put your iPhone in DFU mode to jailbreak it. Pwnage Tool explains how within it. Here’s an iClarified tutorial.
OpenSSH: A package installed by Cydia (and possibly by Pwnage Tool itself), that allows you to browse the file structure of your iPhone from a computer via SSH or SFTP.
yellowsn0w: the first software unlock for OS 2.2.x provided by the Dev-Team. Can be installed with Cydia.
ultrasn0w: the software unlock for OS 3.0 provided by the Dev-Team. Can be installed with Cydia.
bluesn0w: a project involving expanding bluetooth functionality which as of 6/22/2009 was still incomplete. This is not a project by the Dev-Team.
Cracked IPAs: iPhone application files that have had their restrictions removed that you can install through iTunes after following a certain initial procedure. Use these for the purposes of evaluating and comparing products prior to purchase. Support developers.
IPA Prep: Cydia installed hack from xsellize that allows you install cracked IPAs with iTunes. For firmware 2.x only, replaced for FW 3.0 (see AppSync and Installd, below.)
MiPatch: Alternative to IPA Prep, also for FW 2.x.
AppSync: the replacement for IPA Prep & MiPatch for FW 3.0 provided by hackulo.us. Use this or Installd but not both for FW 3.0.
Installd: a similar replacement for IPA Prep & MiPatch for FW 3.0 provided by xsellize. Use this or AppSync but not both for FW 3.0.
brick: when your iPhone is completely locked up, allowing only for the possibility of a total restore.
Be comfortable with working with UNIX paths, file permissions, SFTP and/or SSH, and LAN IPs
Many things can be accomplished on a jailbroken phone by using the provided install tools like Cydia. However, to really take advantage of your jailbroken iPhone, you must have a basic level of comfort with SFTP (secure file transfer protocol) and/or SSH (secure shell), working with UNIX paths, setting file permissions, how your local area network (LAN) is set up, and how to find the IPs of devices on your LAN. If any of this is not something you are comfortable with, I would seriously caution you against jailbreaking at all. In my view, the chief reason to jailbreak if you are not comfortable in this zone is to be able to software unlock your phone.
Ready to do it?
I can’t stress enough that it is important to read and re-read a good tutorial and understand what’s about to happen before pushing buttons.
Please review The Order of Things next.