Although this is now old news, here’s a summary of Apple’s botched Thunderbolt Update that caused kernel panics for many Mac users last month.
When apple introduced their new MacBook Pro and MacBook Air models on 6/11/12, they also announced that they would soon be selling Thunderbolt Ethernet and FireWire adapters. The next day, Apple released a patch called Thunderbolt Software Update (v1.2) to make these adapters compatible with any existing Mac with a Thunderbolt port running OS X 10.7.4.
A lot of people who downloaded and applied this update through Software Update began experiencing kernel panics upon boot. Numerous fixes surfaced, but none were simple, including: Reinstalling OS X 10.7, reapplying the OS X 10.7.4 combo updater, and restoring from backup.
This kernel panic at boot problem was reproduced internally by our staff, but none of our client’s Mac workstations under contract experienced it, because we did not approve this update for automatic patching.
Apple pulled this update on 6/14/12, and re-released it on 6/19/12. Although the Thunderbolt Software Update v1.2.1 is safe to install, Apple has (yet again) received a lot of criticism for releasing a patch that crippled so many Macs.