MacBook Air, MacBook Pro, iMac, Mac mini EFI updates boost net boot
Bug fixes. A quartet of firmware updates for quartet of 2011 Macs, covering a trio of fairly ho hum issues — net boot reliability, HDCP authentication (i.e. Display Port equipped displays) and booting from a USB device. Whether or not you’re affected by these issues, being up-to-date is often its own reward.
• MacBook Air EFI Firmware Update 2.4, download
— 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.
Again, these firmware updates are specific to 2011 models. If in doubt, fire up Software Update.