I got a notification from my MacBook Pro today that an EFI update was available. I hadn’t booted since last Friday, so that explains the lag in notification since this firmware update was actually released about 5 days ago. Anyway, Apple says the update eliminates Optical Drive noise when system boots or wake up from sleep.

Here is the official Apple text:

About MacBook Pro EFI Firmware Update 1.8

This update eliminates the noise made by the optical disk drive during system startup and wake from sleep on MacBook Pro computers. When installation is complete, please run Software Update again, and install SuperDrive Firmware Update 3.0

To complete the firmware update process, please follow the instructions in the updater application (/Applications/Utilities/MacBook Pro EFI Firmware Update.app). The updater will launch automatically when the installation is complete.

Boot ROM or SMC Version Information: http://support.apple.com/kb/HT3706.

MacBookPro5,1 will be updated to MBP51.007E.005
MacBookPro5,2 will be updated to MBP52.008E.005