http://www.macnn.com/articles/13/01/09/cuts.price.on.existing.2m.thunderbolt.cable/
Apple outs MacBook Air EFI update, new Thunderbolt cable
updated 04:59 pm EST, Wed January 9, 2013
Cuts price on existing 2m Thunderbolt cable
Apple has released a new patch for the MacBook Air, EFI Firmware Update 2.6. The code is intended strictly for the current "mid-2012" models, but solves several problems. These include bad colors when connecting HDMI displays, an issue with Windows that caused problems when booting, and a freezing glitch caused by unplugging a Thunderbolt device before waking from standby. The firmware is a 4.76MB download, and requires OS X 10.8.2.
Elsewhere, Apple has started selling a new, shorter Thunderbolt cable at its online store. The accessory is only 0.5m (approximately 1.6 feet) long, but at $29 is also cheaper than the company's standard 2m (6.5 foot) cable. Additionally, Apple has dropped the cost of the 2m cable from $49 to $39.
Fresh-Faced Recruit
Joined: 08-23-11
Didn't solve the problem re HDMI for lots of people - check out the Apple Forum at https://discussions.apple.com/message/20864010#20864010
When using MBA (mid-2012) with MDP to HDMI, screen colors washed out and no amount of screen calibration solves the issue. More work needed from Apple on HDMI.