Apple has released an EFI Firmware Update 2.6 for mid-2012 MacBook Air models. The update fixes several annoying bugs that have been reported in Apple's online help discussion forums. From Apple's knowledge base article:
About MacBook Air EFI Firmware Update 2.6
This update is recommended for MacBook Air (mid 2012) models.
This update fixes a color issue with HDMI displays connected to MacBook Air, resolves an issue with Windows which can prevent MacBook Air from booting properly, and also resolves an issue where unplugging a Thunderbolt device may cause the system to freeze when waking from standby.
As usual, the EFI firmware update weighs in at a tiny 4.76 MB. Be sure you have your MacBook Air plugged into its power supply when installing the update. Users can download the update via Software Update or by downloading it here.