Y'a un com's assez intéressant de musclenerd :
Both the full PwnageTool method and the QuickPwn method of jailbreaking will work for the iPod Touch 2G, but they both still result in a system that (currently) needs to be tethered when the thing reboots. The part of the boot process that hits that snag happens at a level below both of them.
In other words, the ipt2g jailbreak is in many ways the same old jailbreak that we've been able to do since Pwnage 1.0. But when actually booting the jailbroken system, the ipt2G has this tethering snafu that we'd like to fix, to make it easier for everyone to install and use the jailbreak.