Apple on Monday posted an EFI update for its thin-and-light MacBook Air, addressing two wake from sleep issues including a rare problem that causes the computer's fans to spin at full speed unnecessarily.

Apple's MacBook Air EFI firmware update 2.9 targets problems seen on mid-2011 models running OS X 10.9.2 and later.

The release notes say EFI version 2.9 fixes an issue that causes some systems to take longer than expected to wake from sleep. Also addressed is a rare issue that could cause system cooling fans to run at full speed after waking from sleep.

Apple notes the update should only be installed over EFI versions 0077.00, 0077.08, 0077.0E and 0077.0F on OS X 10.9.2 or higher.