Less than a day after Apple released its iOS 4.1 operating system, hackers say they have jailbroken the software for the iPhone 4. In doing so, hackers have shown yet again that they can beat the security systems that Apple puts in place to keep control of its hardware devices.

Hackers almost immediately try to jailbreak Apple’s software whenever there’s a new release so that they can run unauthorized software on the phones. The hack was first announced by a hacker named pod2g who is part of a group called the iPhone Dev-Team. Other hackers confirmed the jailbreak. The exploit targets a low-level part of the operating system and may mean that Apple won’t be able to stop the jailbreakers without a lot of hardware changes.

Previous jailbreaks were plugged pretty quickly, as Apple released patches for its software. Jailbreaking the iPhone is now legal, thanks to a decision by the U.S. Copyright Office in response to an appeal from the Electronic Frontier Foundation.

More than a million iPhone owners are said to have jailbroken their phones so they can get apps from sources other than Apple’s iTunes App Store, or change wireless providers. Copyright law says that if you pay for something, you have the right to use it as you wish as long it is not for commercial benefit.

The iPhone Dev-Team previously took credit for jailbreaking the iPhone 4.0 software in August. Jailbreaking will still void your Apple warranty, so take note if you’re planning on finding jailbreaking software.

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