Apple has issued Hard Drive Update 1.0 software for the iMac Core 2 Duo and the Mac Pro.
The 1.4MB patch is available using Software Update and also for direct download from the Apple support website.
The software is described as including bug fixes and important updates for both Mac systems, which must have Mac OS X 10.4.7 or later installed.
The company warns users installing the software to complete the firmware update process correctly.
"To complete the firmware update process, please follow the instructions in the updater application (/Applications/Utilities/Hard Drive Update 1.0.app). The updater will launch automatically when the Installer closes," Apple says.