By Sam Oliver

Published: 09:40 AM EST (06:40 AM PST)

Hackers have released an untethered jailbreak for the latest version of Apple's mobile operating system, iOS 4.3.1, for all devices but the iPad 2. And jailbreaking has caught the attention of Toyota, which has created a custom iPhone theme to promote its Scion brand.

The iOS Dev-Team on Monday released its latest hack to jailbreak iOS devices, with "PwnageTool 4.3" and "redsn0w 0.9.6rc9" both available for download. The "untethered" jailbreak, which does not require a device to be connected to a computer via USB every time it restarts, works on the iPhone 3GS, GSM iPhone 4, third- and fourth-generation iPod touch, the first-generation iPad, and the second-generation Apple TV.

"The reason the untether won't work as-is on the iPad 2 is that it requires a bootrom or iBoot-level exploit to install, and the iPad 2 is not susceptible to either the limera1n or SHAtter bootroom exploits," the team explained on its official website.

Jailbreaking is a process that allows users to run code and make changes to the iOS mobile operating system that are unauthorized by Apple. One popular use is custom themes and skins that change the look and feel of an iPhone or iPad.

One such skin was released last week for the first time by a major corporation: Toyota released a theme for its Scion 2011 vehicle in Cydia, an alternative application store available on jailbroken devices. Users can find the content by searching for "Scion 2011 Theme" in the Cydia store.

According to ModMyi, the theme was actually developed by Scion, specifically for jailbroken devices, as a promotional tool to push its vehicles. In addition, the company is also running an advertising campaign within Cydia that points to the theme so users can download it.

The report claimed that between 8 and 9 percent of iOS-based devices are jailbroken, and 1.5 million unique users log into Cydia daily, for a total of 4 million to 5 million weekly. "Saurik," who manages Cydia, has estimated that there are 10 million to 15 million jailbroken iOS devices in the wild.

The appearance of an official advertisement from a major corporation will likely add some credibility to the jailbreaking community and Cydia in the mainstream. Jailbreakers also received a boost from the U.S. government last July, when the process was declared legal.



While jailbreaking can be used for entirely legal purposes such as themes and unauthorized applications, it can also be used for illegal purposes, such as stealing software from Apple's App Store. That reason, along with security concerns and other issues, has caused Apple to fight the practice.

However, Apple also removed a jailbreak detection feature from iOS 4.2 in December. The application programming interface, which first appeared in iOS 4.0 last June, had allowed third-party mobile device management applications to check for unauthorized modifications to system files.