A new exploit discovered in the iPhone hardware, or more specifically, the A4 processor, makes the iPhone, iPod touch 4G and the iPad jailbroken for life, becuase the exploit is found in the hardware, and thus it cann't be updated without updating the hardware itself.
With this exploit, Apple may update their hardware on the iPhone 4, iPod touch 4G and iPad to prevent hackers from exploiting the device. This news comes only a day after Apple released iOS 4.1 and iPod touch 4G shipped to customers.
The exploit is similar to that of the iPhone 3GS, old bootrom, before Apple released an updated hardware revision to block the exploit. However, this's still a tethered jailbreak, meaning you won't be able to reboot the device without having it connected to your Mac or PC.