Compared to a PC, phones and tablets are fairly locked-down devices. Jailbreaking, rooting, and unlocking are all ways of bypassing their limitations, and doing things that manufacturers and carriers don’t want you to do.
Some countries have laws that prevent you from doing these things with the devices you paid for and legally own — we won’t get into those laws here.
Image Credit: Blake Patterson on Flickr
Jailbreaking
Jailbreaking is the process of removing the limitations put in place by a device’s manufacturer. Jailbreaking is generally performed on Apple iOS devices, such as the iPhone or iPad. Jailbreaking removes the restrictions Apple puts in place, allowing you to install third-party software from outside the app store. Some people may have the perception that jailbreaking is only used for piracy, but this isn not the case — jailbreaking allows you to do things like change your iPhone’s default browser and mail client. Essentially, jailbreaking allows you to use software that Apple doesn’t approve.
Jailbreaking can be performed on other devices with similar limitations. For example, there is now a Microsoft Surface RT jailbreak that allows you to install unapproved desktop programs. (By default, Windows RT systems only allow you to run desktop applications written by Microsoft.) However, the desktop apps must be compiled for ARM, so you can’t run any Windows desktop programs you already have, although open-source applications could be tweaked and recompiled for the Windows desktop on ARM.
Companies like Apple and Microsoft don’t want you jailbreaking to get past a device’s limitations — so you can change the default programs on iOS or run third-party desktop applications on Windows RT. To perform a jailbreak, someone has to find a security vulnerability that allows them to “exploit” the device and get around the manufacturer safeguards.
Android allows users to install third-party applications from outside Google’s app store out-of-the-box and doesn’t need to be jailbroken.
Rooting
Rooting is the process of gaining “root access” to a device. This is generally performed on Android devices, but rooting can also occur on other devices based on Linux, such as Nokia’s now-retired Symbian operating system.
On Linux and other UNIX-like operating systems, the root user is essentially the same as the Administrator user on Windows. After rooting, you can grant specific applications access to root permissions, allowing them to do almost anything they want to the operating system. For example, an application with root permissions could uninstall system applications, install low-level system binaries, revoke permissions installed apps require, and do other crazy things. Almost anything you can do on a proper Linux system, you can do with root access on your phone.
Rooting gets around Android’s security architecture and could potentially cause problems if users don’t know what they’re doing, so Android doesn’t come rooted.
On some devices, rooting may need to be accomplished via a security exploit. Just like jailbreaking, manufacturers generally don’t want you rooting. On some devices, such as Nexus devices (which are also intended for developers), rooting does not require a security vulnerability.
Unlocking a Bootloader
Android is an open-source operating system, so anyone can take the Android source code and create their own version of it. This allows custom ROMs like Cyanogenmod to exist. Lots of custom ROMs exist for Android — everything from large projects that support a variety of devices to custom ROMs with a few theme patches some kid whipped up in his spare time.
However, many Android phones come with locked bootloaders. A locked bootloader won’t boot anything but the manufacturer-approved version of Android that comes with the device. Unlocking the bootloader allows you to install custom ROMs — alternate versions of the Android operating system.
This isn’t just useful to geeks — Cyanogenmod brings new versions of Android to devices that manufacturers no longer update. It’s a more vanilla Android experience, too — many people like it because it is an alternative to the manufacturer-customized user interfaces most Android devices come with.
Unlocking a device’s bootloader may also require a security exploit, although companies like HTC and Motorola allow unlocking some devices. Nexus devices (which are also intended for developers) can be easily unlocked.
Unlocking a boot loader can theoretically allow you to install non-Android operating systems, too. For example, you can install Ubuntu for phones or WebOS on a Galaxy Nexus with an unlocked bootloader. The desktop version of Ubuntu can be installed on the Nexus 7, too. Of course, the operating system must be built to be compatible with a specific device. These operating systems probably aren’t particularly stable — but developers can use the devices to run an alternate operating system while they work on it.
Image Credit: Johan Larsson on Flickr
Unlocking a Phone
Many phones, particularly phones that come subsidized with a contract, come “locked” to a specific carrier. The phone is set up so that it can only be used on that carrier’s network. If you insert a SIM card from a competing carrier into the phone, you will see a message indicating that the phone is locked and cannot be used with the SIM card.
Unlocking a phone allows you to use it with a different SIM card — either to use a different carrier while travelling or to take your current phone with you while switching to a new service provider.
You will generally need an unlock code to unlock the phone. Many carriers will unlock phones once your contract is up, while phones bought outright without a contract may not be locked to a carrier at all. There are ways to unlock phones without a carrier’s permission, too.
Image Credit: Kai Hendry on Flickr
Not everyone has to jailbreak, root, or unlock their devices. However, the option is there — and now you know why you might want to.