Rooting (Android OS)
Encyclopedia
Rooting is a process that allows users of mobile phones
and other devices running the Android operating system to attain privileged control (known as "root access
") within Android's Linux subsystem with the goal of overcoming limitations that carriers and manufacturers put on some devices. It is analogous to jailbreaking on devices running the Apple iOS operating system.
. This is because in the stock configuration (unrooted), user-installed applications do not have direct access to the flash memory chip on the device and, thus, are not able to replace or modify the operating system itself.
Rooting is also necessary for certain applications and widgets that require additional system and hardware rights such as for rebooting the phone, certain backup utilities, and other access to other hardware such as status LEDs. Rooting is also needed to disable or remove manufacturer-installed applications such as City ID
. Rooting the phone typically also includes installing an application called Superuser that supervises which applications are granted root rights.
In contrast to iOS jailbreaking, rooting is not needed to run applications not distributed by the official Android Market (sometimes referred to as "side-loading"). However some carriers, like AT&T, prevent the installation of applications not on the Android Market
in firmware
, however the new Samsung Infuse 4G from AT&T allows running applications not downloaded from the market.
One of the downsides to rooting is that some phone makers consider it to be "modifying" the phone, which violates the warranty. However, as long as the phone is unrooted (the process for doing so varies by phone) before the user tries to use his or her warranty, there isn't an easy way for the warranty provider to know that the phone was previously rooted. Another downside would be the potential risk of bricking the device. The term "bricking" is used to describe a device which has had its software modified improperly to the point where it is no longer functioning.
ing a security weakness in the firmware shipped from the factory. For example, shortly after the T-Mobile G1 was released it was quickly discovered that anything typed using the keyboard was being interpreted as a command in a privileged (root) shell. Although Google quickly released a patch to fix this, a signed image of the old firmware was leaked giving people the ability to downgrade and use the original exploit to gain root access. Once this exploit is found, a custom recovery image that does not check the digital signature
of a firmware update package can be flashed. In turn, using the custom recovery, a modified firmware update can be installed that typically includes the utilities (for example the Superuser app) needed to run apps as root.
The Google-branded
Android devices, the Nexus One
, Nexus S
and the Galaxy Nexus
, can have their boot-loaders unlocked by simply running the command "fastboot oem unlock" from a computer connected to the device while it is in boot-loader mode. After accepting a warning the boot-loader will be unlocked so that a new system image can be written directly to flash without the need for an exploit.
Recently, Motorola
, LG Electronics
and HTC Corporation have added security features to their devices at the hardware level in an attempt to prevent retail Android devices from being rooted. For instance, the Motorola Droid X
has a security boot-loader that will put the phone in "recovery mode" if unsigned firmware is loaded onto the device. This protection was defeated 6 days after the Motorola Droid X was released to the general public.
.
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
and other devices running the Android operating system to attain privileged control (known as "root access
Superuser
On many computer operating systems, the superuser is a special user account used for system administration. Depending on the operating system, the actual name of this account might be: root, administrator or supervisor....
") within Android's Linux subsystem with the goal of overcoming limitations that carriers and manufacturers put on some devices. It is analogous to jailbreaking on devices running the Apple iOS operating system.
Description
Most retail devices running the Android operating system must be rooted in order to install custom versions of the Android system such as CyanogenModCyanogenMod
CyanogenMod is an after-market replacement for the firmware of over sixty cell phones and Internet tablets. Based on the Android mobile computer operating system, it offers features and options not found in the official firmware distributed by vendors of these devices.Features supported by...
. This is because in the stock configuration (unrooted), user-installed applications do not have direct access to the flash memory chip on the device and, thus, are not able to replace or modify the operating system itself.
Rooting is also necessary for certain applications and widgets that require additional system and hardware rights such as for rebooting the phone, certain backup utilities, and other access to other hardware such as status LEDs. Rooting is also needed to disable or remove manufacturer-installed applications such as City ID
City ID
City ID is a caller information software product created by Cequint Incorporated. City ID displays the North American city and state of a calling phone number based upon the phone number's area code and exchange....
. Rooting the phone typically also includes installing an application called Superuser that supervises which applications are granted root rights.
In contrast to iOS jailbreaking, rooting is not needed to run applications not distributed by the official Android Market (sometimes referred to as "side-loading"). However some carriers, like AT&T, prevent the installation of applications not on the Android Market
Android Market
Android Market is an online software store developed by Google for Android OS devices. Its gateway is an application program called "Market", preinstalled on most Android devices, allows users to browse and download mobile apps published by third-party developers...
in firmware
Firmware
In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...
, however the new Samsung Infuse 4G from AT&T allows running applications not downloaded from the market.
One of the downsides to rooting is that some phone makers consider it to be "modifying" the phone, which violates the warranty. However, as long as the phone is unrooted (the process for doing so varies by phone) before the user tries to use his or her warranty, there isn't an easy way for the warranty provider to know that the phone was previously rooted. Another downside would be the potential risk of bricking the device. The term "bricking" is used to describe a device which has had its software modified improperly to the point where it is no longer functioning.
Process
The process of rooting varies widely by device. It usually includes exploitExploit (computer security)
An exploit is a piece of software, a chunk of data, or sequence of commands that takes advantage of a bug, glitch or vulnerability in order to cause unintended or unanticipated behavior to occur on computer software, hardware, or something electronic...
ing a security weakness in the firmware shipped from the factory. For example, shortly after the T-Mobile G1 was released it was quickly discovered that anything typed using the keyboard was being interpreted as a command in a privileged (root) shell. Although Google quickly released a patch to fix this, a signed image of the old firmware was leaked giving people the ability to downgrade and use the original exploit to gain root access. Once this exploit is found, a custom recovery image that does not check the digital signature
Digital signature
A digital signature or digital signature scheme is a mathematical scheme for demonstrating the authenticity of a digital message or document. A valid digital signature gives a recipient reason to believe that the message was created by a known sender, and that it was not altered in transit...
of a firmware update package can be flashed. In turn, using the custom recovery, a modified firmware update can be installed that typically includes the utilities (for example the Superuser app) needed to run apps as root.
The Google-branded
Google Nexus
The Nexus is a series of Android smartphones produced by Google in co-operation with selected hardware companies. The purpose of the Nexus phones is to offer a "pure Android experience", in which the phones come free of carrier or manufacturer modifications and with an unlockable bootloader to...
Android devices, the Nexus One
Nexus One
The Nexus One was Google's flagship smartphone manufactured by Taiwan's HTC Corporation. It became available on January 5, 2010 and uses the Android open source mobile operating system...
, Nexus S
Nexus S
The Nexus S is a smartphone co-developed by Google and Samsung and manufactured by Samsung Electronics. It was the first smartphone to use the Android 2.3 "Gingerbread" operating system, and the first Android device to support Near Field Communication in both hardware and software...
and the Galaxy Nexus
Galaxy Nexus
The Galaxy Nexus is a touchscreen slate Android smartphone developed by a partnership between Samsung and Google. The phone and operating system were developed collaboratively by engineers from both companies. It is the third generation successor to Google’s previous flagship phones, the Nexus One...
, can have their boot-loaders unlocked by simply running the command "fastboot oem unlock" from a computer connected to the device while it is in boot-loader mode. After accepting a warning the boot-loader will be unlocked so that a new system image can be written directly to flash without the need for an exploit.
Recently, Motorola
Motorola
Motorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...
, LG Electronics
LG Electronics
LG Electronics is a global electronics and telecommunications company headquartered in Yeouido, Seoul, South Korea. The company operates its business through five divisions: mobile communications, home entertainment, home appliance, air conditioning and business solution...
and HTC Corporation have added security features to their devices at the hardware level in an attempt to prevent retail Android devices from being rooted. For instance, the Motorola Droid X
Motorola Droid X
The Motorola Droid X is a smartphone manufactured by Motorola Mobility, Inc. that runs the Android 2.3 software; the version of the hardware released in Mexico is called the Motorola Motoroi X. The Droid X has been distributed since July, 2010 by Verizon Wireless in the United States and Iusacell...
has a security boot-loader that will put the phone in "recovery mode" if unsigned firmware is loaded onto the device. This protection was defeated 6 days after the Motorola Droid X was released to the general public.
United States
On July 26, 2010, the U.S. Copyright office announced a new exemption making it officially legal to root a device and run unauthorized third-party applications, as well as the ability to unlock any cell phone for use on multiple carriersSIM lock
A SIM lock, simlock, network lock or subsidy lock is a capability built into GSM phones by mobile phone manufacturers. Network providers use this capability to restrict the use of these phones to specific countries and network providers...
.
See also
- Android (operating system)
- Google NexusGoogle NexusThe Nexus is a series of Android smartphones produced by Google in co-operation with selected hardware companies. The purpose of the Nexus phones is to offer a "pure Android experience", in which the phones come free of carrier or manufacturer modifications and with an unlockable bootloader to...
- Android Dev PhoneAndroid Dev PhoneThe Android Dev Phone is a SIM-unlocked and hardware-unlocked Android device that is designed for advanced developers. While developers can use regular consumer devices purchased at retail to test and use their apps, some developers may choose not to use a retail device, preferring an unlocked or...
- CyanogenModCyanogenModCyanogenMod is an after-market replacement for the firmware of over sixty cell phones and Internet tablets. Based on the Android mobile computer operating system, it offers features and options not found in the official firmware distributed by vendors of these devices.Features supported by...
- Jailbreaking
- Hacking of consumer electronicsHacking of consumer electronicsHacking has expanded from applying strictly to computers to consumer electronics in general. Hacking provides users with the ability to customize and modify their devices...
External links
- Rooting Explained + Top 5 Benefits Of Rooting Your Android Phone - androidpolice.com
- Android – G1 – Root Access Why & How (Android Social Media)
- How to Hack Your Android Phone (and Why You Should Bother) - Read Write Web
- Why Root - android-dls.com
- Five Great Reasons to Root Your Android Phone - LifeHacker.com
- "The Always Up-To-Date Guide to Rooting Any Android Phone" - LifeHacker.com