How to unlock your iPhone through jailbreaking

When the original iPhone debuted in 2007, the only way to use software was through web apps, limited to those approved by Apple. But with the release of the iPhone 3G and the App Store in 2008, iPhone owners gained access to thousands of apps that could be installed directly onto the phone. Today, over 30,000 apps are available in the App Store [source: 148Apps]. While that may seem like a lot, many users desire more [source: Von Lohmann and Granick]. These are the jailbreakers.

Jailbreaking is popular because the iPhone and the App Store come with certain restrictions. Apple limits basic features that other phones provide by default, such as video recording, custom ringtones, photo zoom, and the ability to customize the interface, including icons. Jailbreaking removes these restrictions and grants users access to third-party apps—those that Apple has rejected from the App Store for various reasons like being deemed objectionable, inappropriate, or redundant. These apps are usually distributed directly by the developers to bypass Apple's distribution fees.

However, it's not only the unauthorized apps that draw people to jailbreak their iPhones. For those with a technical mindset, jailbreaking can unlock additional possibilities beyond just adding video apps. The iPhone runs on a variant of Mac's OS X operating system, which is Unix-based. This means that technically, you can jailbreak your iPhone and install Unix applications such as a lightweight Apache Web server with PHP or an SSH daemon, transforming the iPhone into a compact computer.

One of the main reasons people jailbreak an iPhone is to unlock it. While jailbreaking and unlocking are often mixed up, they are two distinct actions. Unlocking an iPhone removes the SIM lock, allowing it to work with any carrier, not just the official, Apple-approved provider, which varies depending on the country.

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Jailbreaking your iPhone

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Jailbreaking an iPhone does not automatically unlock it (though unlocking requires jailbreaking first). Instead, it is a hack that opens up the phone’s firmware, allowing you to install third-party applications. Firmware is a combination of both hardware and software; it contains the code that guides how the iPhone operates, what features are activated, and what security patches are necessary. Apple periodically releases firmware updates to enhance features and fix bugs.

When an iPhone starts up, it follows a series of steps known as the "chain of trust," where different software components are checked in a specific order. It starts with boot ROM, then moves on to load the low-level bootloader (LLB), which controls data storage and transfers between devices, such as flash memory. Following that, iBoot loads, then the operating system kernel, and finally the kernel loads user applications. During each step, the system checks for unauthorized software.

Jailbreaking an iPhone involves modifying or ‘patching’ the iBoot and the operating system kernel. This alteration prevents them from performing the signature checks that would normally verify whether the software is authorized or unauthorized.

The process of jailbreaking can vary depending on the iPhone model (and iPod Touch), the firmware version, and whether you're using a Windows or Mac computer. To begin, you'll need an iPhone, a computer with the latest version of iTunes, a jailbreaking program with clear instructions, and some time. Additionally, you'll need to know which firmware version your device is running.

While we’re not providing the download here, with a bit of online searching, you can find the necessary tools and guides, usually with detailed instructions and screenshots. Popular jailbreaking programs include QuickPwn (for iPhone 3G with firmware 2.0+), and PwnageTool (for first- and second-generation iPod Touches). These tools come from the iPhone dev team. After jailbreaking, you can access third-party apps through software like Cydia, which serves as a marketplace for unsanctioned apps.

Staying up to date with jailbreaking software is like a never-ending game of cat and mouse—Apple rolls out firmware updates, and hackers rush to create a jailbreak for the new version.

Issues with Jailbreaking Your iPhone: Second Thoughts

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If the thought of hacking your phone worries you, there’s a partial safety net. When you choose to jailbreak your phone, you do so knowing there’s a risk of damaging it. While phones can sometimes be restored to their original state by reinstalling the firmware through iTunes, there’s no guarantee. In the worst-case scenario, your phone could become an expensive paperweight, often called an iBrick.

Warning: Jailbreaking is not supported by Apple (hence the name 'jailbreaking'). This action voids your warranty, and any new firmware updates from Apple will erase any prior jailbreaking efforts as they overwrite them.

Security issues also arise. When you purchase apps from Apple’s App Store, they have been vetted for safety. However, with unsanctioned third-party apps, there’s no way to be sure of what you’re installing — it could be the latest tool to upload a video to YouTube or a harmful piece of software. You won’t know until it’s installed.

Furthermore, Apple’s comments to the U.S. Copyright Office in early 2009, as part of the 2009 Digital Millennium Copyright Act (DMCA) triennial rulemaking, stated that jailbreaking an iPhone is a violation of the DMCA and constitutes copyright infringement.

The DMCA grants Apple the authority to block any unauthorized software from working on their devices. Downloading third-party apps without Apple’s approval places you in violation because your phone is no longer under their security controls. Copyright infringement is also a concern because jailbreaking requires modifying Apple’s code, raising the question of whether reverse engineering is fair use or infringement — that’s a legal matter for the courts to decide.