Firmware Updates for iMac, Mac mini, MacBook Air, and MacBook Pro
Apple has released a quartet of firmware updates for models released in 2011: iMac EFI Firmware Update 1.9, Mac mini EFI Firmware Update 1.6, MacBook Air EFI Firmware Update 2.4, and MacBook Pro EFI Firmware Update 2.7. Each update improves reliability when booting from the network, addresses issues with HDCP authentication after rebooting, and fixes a problem with boot device selection when a USB storage device is hot-plugged. As with any firmware update, you should read the installation instructions carefully before installing and avoid
interrupting the update process. To ensure you get an update only if it’s necessary, we recommend relying on Software Update; if an update doesn’t appear for you, it’s not appropriate for your Mac. (Free, each approximately 4 MB)
EFI firmware update 2.7 was installed but every time I run system update it tries to install the update again. Any help would be appreciated. Thanks.
What happens if you let it install again? Perhaps it didn't finish successfully the first time?