Legality
Australia
Rooting of any device is legal if the purpose is to run legal apps.
[edit]Europe
The Free Software Foundation Europe argues that it is legal to root or flash any device. According to the European Directive 1999/44/CE, replacing the original operating system with another does not void the statutory warranty that covers the hardware of the device for two years unless the seller can prove that the modification caused the defect.[18]
[edit]United States
On July 26, 2010, the United States 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 carriers.
On October 28, 2012, the US Copyright Office updated their exemption policies. The rooting of smartphones continues to be legal "where circumvention is accomplished for the sole purpose of enabling interoperability of [lawfully obtained software] applications with computer programs on the telephone handset." However, the U.S. Copyright office refused to extend this exemption to tablets, arguing that the term "tablets" is broad and ill-defined, and an exemption to this class of devices could have unintended side effects.