Jailbreaking an iOS device has been in a murky grey area legally, but it just got a lot clearer: today, the US Copyright Office issued an exemption to the Digital Millenium Copyright Act that jailbreaking a device does not violate US copyright law. However, it's not a blanket ruling, because tablets are, according to the US Copyright Office, “difficult to define.” The Electronic Frontier Foundation, along with a host of other electronic freedom organiziations, has been appealing to the Copyright Office to make exemptions to the DMCA legalizing the customization of a device you own.
Ubergizmo , It's Legal to Jailbreak Your iPhone, But Not an iPad, It's Legal to Jailbreak Your iPhone, But Not an iPad
