http://support.apple.com/kb/DL1337
This update is recommended for MacBook Air (11-inch and 13-inch, late 2010)
models.
This update resolves a rare issue where MacBook Air boots or wakes to a
black screen or becomes unresponsive. This update is recommended for all 11
-inch and 13-inch MacBook Air (late 2010) models.
The MacBook Air EFI Update will update the EFI firmware on your notebook
computer. Your computer's power cord must be connected and plugged into a
working power source. When your MacBook Air restarts, a gray screen will
appear with a status bar to indicate the progress of the update. It will
take several minutes for the update to complete. Do not disturb or shut off
the power on your MacBook Air during this update.
