Can I Upgrade to Mac OS X 10.5.7 with a Jailbroken iPhone?
The short answer is yes. In fact, according to the iPhone Dev-Team, the latest version of Mac OS X is more iPhone jailbreak-friendly than the previous version. This is due to the fact that version 10.5.6 prevented users from putting the iPhone into DFU mode.
The Dev-Team states, "The new 10.5.7 Leopard update is safe. In fact it's more jailbreak-friendly than 10.5.6, since the DFU-mode bug is gone."
According to Apple, the OS X update includes "general operating system fixes that enhance the stability, security and compatibility of your Mac." One security enhancement that only appears after the OS X 10.5.7 upgrade is a Safari 4 Beta security update.
iTunes 8.2 along with Mac OS X 10.5.7 is also expected to add note-syncing functionality. This will backup iPhone Notes app content to the Mac.