Specifically, the update [772KB] is for 20-inch and 24-inch aluminum iMac computers with the ATI Radeon HD 2600 Pro graphics processor, running Mac OS X 10.4.10 with iMac Software Update 1.2.1 for Tiger, or Mac OS X 10.5 with iMac Software Update 1.3 for Leopard.
The patch updates the graphics firmware on the ATI Radeon HD 2600 PRO card to address issues that may have caused the systems to freeze, Apple explained in a tech note.
Not every 20-inch and 24-inch aluminum iMac computer requires this update, however. Users who are not automatically presented with the update via the Mac OS X Software Update mechanism do not need it, the company explained. Users who manually download the update and attempt to install it on an ineligible computer, you will receive an error message.
If you manually download the update and receive the following error message when selecting a volume, "You cannot install iMac Graphics Firmware Update on this volume. Your computer does not need this update," one of two conditions exist:
You have not installed the iMac Software Update 1.2.1 for Tiger or iMac Software Update 1.3 for Leopard. From the Apple menu, select Software Update and install the appropriate software update, and then reinstall iMac Graphics Firmware Update 1.0.You have already installed this update.