Apple just released Thunderbolt software update 1.2.1. The 520KB update adds support for the $29 Apple Thunderbolt to Gigabit Ethernet adapter announced at the Worldwide Developers Conference:

Adds support for the Apple Thunderbolt to Gigabit Ethernet Adapter

It does not destroy your Mac like Apple’s previous try at this update. Interestingly, it also does not support the new Retina MacBook Pro. Go grab it in Software Update on supported machines.

via MacRumors