Apple quietly issues firmware fix for Thunderbolt flickering issues on 24-inch LED Cinema Displays
MacRumors points to a thread on the Apple Discussion Forums where Apple posted a firmware fix for the flickering issue on the Apple 24-inch LED Cinema Display stemming from Thunderbolt. The problem is specifically related to the 24-inch LED Cinema Displays connected to your Thunderbolt-enabled Mac rather than the glitches on the 2011 MacBook Pro causing flickering and lock ups under heavy load. It should be applied only when the display is connected to a Thunderbolt-enabled Mac. It is interesting that Apple decided to release the fix on the forum rather than its Support Downloads page. From the release notes accompanying the 926KB download:
The 24-inch LED Cinema Display Firmware Update addresses an issue that may cause intermittent display flickering. This firmware will only install on the Apple 24-inch LED Cinema Display when it is connected to a Thunderbolt-enabled Mac.
This firmware update may not resolve the flickering issue if a Mini DisplayPort extender cable is used.
Some USB and FireWire devices may prevent firmware updates from installing correctly; disconnect non-essential devices and use only an Apple keyboard and mouse to apply the update.