Hackers have released software which allows users of Apple's iPhone 4 to bypass the App Store and install third-party software of their own choice.
The jail-breaking process has been demonstrated on the iPhone 4 but was not publically available until now.
JailbreakMe allows owners of all iPhone OS devices, including the iPhone 4 and the iPad, to install applications from sources other than Apple's App Store.
This means that applications that fail to pass Apple's strict guidelines can be distributed through unauthorised application repositories. Typically these are accessed through a dedicated application, the most popular of which is Cydia.
Last week, the US Copyright Office approved the jail-breaking practice, meaning that Apple cannot legally force customers to stay within the confines of its walled garden App Store.
Such a move could hurt Apple's revenues, but the percentage of iPhones and iPads that are jail-broken is thought to be very low.
The procedure poses potential security risks as applications on the repositories are typically not vetted for malware, and Apple has released updates to its OS designed to nullify jail-breaks.
JailbreakMe is the latest release from the iPhone Dev Team hacker collective which has been playing cat and mouse with Apple for years.
However, as the software from the iPhone Dev Team gets more sophisticated, it has made it easier than ever to unshackle iPhone OS devices.
While this update does not incorporate the software carrier unlock many had been hoping for, it should not be long before iPhone 4 users can slot in the SIM card of their choice.
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