Apple has posted firmware updates on
its support Web site
for Intel-based Macs — MacBooks, MacBook Pros, Mac minis, Mac Pros and iMacs are all included on the list.
The update, which changes the Extensible Firmware Interface (EFI) firmware used on these computers, fixes several Boot Camp, startup, and wake-from-sleep issues on these machines.
Please read the instructions thoroughly before attempting these updates. Also, a firmware restoration CD image is available for download, to help recover computers that may not handle this update correctly for whatever reason.