How would you like to have two iPhones in one? NerveGas of iPhone Dev Team reveals that the team has been using dual-booting to jailbreak the iPhone for months. The team has decided to release the hack enabling iPhone users to boot multiple versions of the iPhone software/OS "from" the handset.

This should present iPhone users with quite an advantage once the 2.0 firmware is out, meaning they'll be able to have a bootable jailbroken software version, as well as a non-jailbroken software version available at the same time on their device. Partition-making is involved:

"The dev team has been using dual-booting to jailbreak the iPhone for several months now, however now that several more advanced techniques have been developed (many of which are still private), I thought it apropos to release this cool hack for those who would like to dual boot multiple versions of the iPhone software (or other OS's) from their handset. It's a neat little hack that I think might be useful for developers playing with 1.2, which appears to disable the radio (phone calls).

I'll walk you through a sample jailbreak scenario with 1.1.4, using 1.1.1, to show you what I mean. To do this, you will carve out a new partition on the iPhone and install version 1.1.1 on it. You'll then upgrade the iPhone to v1.1.4, which will leave the new partition intact. You can then dual-boot the iPhone, allowing you to mount 1.1.4's partition using the 1.1.1 partition," says the iPhone Dual Boot / Jailbreak overview.

As some of you may already know, Softpedia doesn't condone hacking/jailbreaking your Apple portables. The iPhone Dev Team also says that the jailbreaking process involved by the instructions they've made available "can result in PERMANENT, IRREPARABLE DAMAGE to your iPhone," so accepting to go forward with it is at your own risk.

Via iPhone Atlas