The iPhone Dev-Team has confirmed that updating to iTunes 8.2 will make the current versions of QuickPwn and Pwnage Tool inoperable. They are warning users who wish to jailbreak iPhones to wait until the new versions of their tools are available before upgrading iTunes to the new version.
The Dev-Team plans to release updated jailbreaking software after Apple makes a public release of iPhone OS 3.0. An update to the unlocking software yellowsn0w will also have to wait.
According to the Dev-Team, any possible release of a yellowsn0w version for basebands newer than 02.28.00 would only come after iPhone OS 3.0 is out of beta.
Jailbreaking the iPhone provides added functionality to the user by making it possible to run software not approved by Apple. The yellowsn0w tool is available on Cydia and allows jailbroken iPhones to be used with any GSM carrier.The iPhone Dev-Team has determined that iTunes 8.2 has updated a low-level USB protocol and this inadvertently breaks the jailbreak tools.
From the Dev-Team Blog, the reasons jailbreakers and yellowsn0w-users should NOT update iTunes to version 8.2:
Newest iPhone FAQs
It breaks your ability to use QuickPwn, PwnageTool, and iPhone Tunneling Suite (ssh over usb). We don’t think this is a deliberate breakage of these tools. It’s just that Apple has updated a low-level USB protocol that normally only Apple cares about (but jailbreakers care about).
So far, the only appreciable change to iTunes 8.2 is the Genius function working on videos.
On an added note, the Dev-Team also thinks the iTunes 8.2 update may break the Palm Pre's ability to communicate with iTunes.