...from: http://support.apple.com/kb/DL1756?viewlocale=en_US&locale=en_US

[Download icon] MacBook Air EFI Firmware Update 2.9.1 Downloadhttp://support.apple.com/downloads/DL1756/en_US/MacBookAirEFIUp2.9.1.dmg

This update replaces EFI Firmware Update 2.9 and is recommended for MacBook Air (Mid 2011) models. This update addresses an issue where systems may take longer to wake from sleep than expected and fixes a rare issue that may cause fans to run at full speed after waking from sleep.

Post Date: Jul 30, 2014 File Size: 4.3 MB System Requirements

* OS X 10.9.2 and later * MBA41.0077.B11