Apple has released an important software update for all mid-2012 MacBook Air models. The EFI firmware update is available now via Software Update in the Mac App Store. Today’s 2.6 update addresses issues with coloring on HDMI-connected displays, booting into Windows via a tool like Boot Camp, and a Thunderbolt glitch.
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.
Source: Apple
