About MacBook Air EFI Firmware Update 2.4
This update fixes several issues to improve the stability of MacBook Air (Mid 2011) computers and is recommended for all users.
This update improves the reliability of booting from the network, addresses an issue that can prevent HDCP authentication after a reboot, and resolves an issue with boot device selection when a USB storage device is hot-plugged.
The MacBook Air EFI Firmware Update will update the EFI firmware on your 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.