Along with its firmware updates for the Mac Pro and Xserve, Apple released Firmware Restoration CD 1.8 for Intel-based Macs Monday evening. The restoration CD is designed to restore your Mac's firmware and restore the default settings for some preferences.
According to Apple's release notes, "You can only use this to restore the firmware after an interrupted or unsuccessful update. If your computer is already in this state, you'll need to download the software and create the CD on another Macintosh computer, or you can take your computer to an Apple Store or Apple Authorized Service Provider to restore your firmware."
The Restoration CD download is a disc image that must be installed on a CD before being used. The image can be installed on a CD with a PowerPC or Intel-based Mac, but can restore the firmware only on Intel-based Macs.
Firmware Restoration CD 1.8 is compatible with Mac Pro and Xserve models from early 2009. Other Mac models require different versions of the Firmware Restoration CD.
The Firmware Restoration CD 1.8 disc image is available for download at the Apple Support Web site.