If you have upgraded to Apple’s latest operating system Mac OS X Mountain Lion and need to jailbreak an iPhone, iPad or iPod touch with iOS 5.1.1, you’re in luck.
Absinthe 2.0 currently doesn’t work normally on Mountain Lion, but there is a easy way to make it function normally.
Step 1: Download Absinthe 2.0 v2.0.4 from here (if you don’t already have it.)
Step 2: Right click on on the Absinthe icon and click “Show Package Contents”.
Step 3: Navigate to Contents-> MacOS and right click on Absinthe 10.6, then select Open with Terminal.
Step 4: The Absinthe 2.0 user interface will open for your to jailbreak your iDevices with iOS 5.1.1. Just follow the on screen instructions in the Absinthe application and let terminal run in the background.