Apple keeps trying to foil the efforts of the iPhone Dev Team with intentional roadblocks built into each successive build of the iPhone/iPod touch firmware - and the newly-minted firmware 2.1 is no exception.
Each time Apple releases an update firmware it breaks the installed jailbreak and prevents the device from being pwned. If you haven't been following the saga surrounding the Pwnage Tool, the iPhone dev team taunts the official iPhone team with this little gem on their blog:
Apple can’t fix the bug we’ve exploited in PwnageTool unless they fix their hardware.
Na, na, na na, na.
But then they admit that Apple has suceeded in finding other ways to make like difficult for jailbreakers:
...one way they can try to combat Pwnage for existing hardware is to program iTunes to detect and prevent the Pwnage exploit. In fact, they’ve already done that in iTunes 8. The screenshot below from iTunes 8 using a Pwned ipsw (with an unPwned device attached) is one example.
Then they add this joyous little nugget:
The nice thing about iTunes decisions is that we can provide you with patches to counter them. We have one such patch already for Mac iTunes 8 for iPod touch. We’ll be working out the full suite of patches for all the combinations over the next week.
Personally I'm done with the jailbreaking for the time being. Mostly because I like to be able to install the new Apple firmware updates when they're released but also because the majority of software that I need is available from the App Store.
The only things that I'd consider jailbreaking for are themes and tethering. What about you?