Many users on OS X Yosemite trying to install the iOS 8 GM seed have run into a serious issue, however. The current version of iTunes 12 crashes after erasing a user’s device, leaving them stranded in DFU mode with no way to actually get back to a usable state (unless they have a Mavericks machine handy). If you are running Yosemite exclusively, it’s probably best to wait for an iTunes 12 update before attempting to install the GM.