MacBook Air EFI Firmware Update 2.9.1
System Requirements:
OS X 10.9.2 and later
File Size: 4.3 MB
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.
After the update, the EFI ROM will be MBA41.0077.B11