Apple released a new build of the iPhone SDK uitgebracht. The new SDK has been released for the developers who’d like to create applications for iPhone firmware 2.1. No details have been released so far on what has been changed except for a reference found to a firmware 2.1.1. iPhone SDK build 9M2517 can only be installed on Mac OS X 10.5.4 or higher.

In one of the readme files you find:

“iPhone OS 2.1.1 for iPod touch. Developers using an iPod touch (2nd generation) with iPhone OS 2.1.1 will need to create the following symlink […]”

Download the new sdk on the developerwebsite Apple.