This update is only available for the 1.8 GHz single-processor Power Mac G5 computer (Late 2004). It supports Mac OS X 10.4.3 and later. This update will also improve the reliability of your Power Mac G5, especially after it has been idle for two hours.
Software Update is a tool that ensures you have Mac OS X v10.4.3 installed on your Mac. Software Update can be used by selecting Apple/ Software Update. The Software Update window will open and display a list with available updates. Click on the items that you wish to install and click Next.
Note: To use Software Update, your Power Mac G5 must have an Internet connection.
Follow these instructions to update your Power Mac G5's firmware. These instructions can be printed so that they are readily available when you upgrade your firmware.
Do not cancel or interrupt the update once it has begun. The update takes more than one minute. The update causes Power Mac fans to run at maximum speed. After the update is completed, they will return to normal.
For more information, please visit this website: Power Mac G5 Late 2004. 1.8GHz models stop responding randomly
You can download the Power Mac G5 (Late 2004,) System Firmware update for Mac OS X 10.3.9 by visiting this website: Power Mac G5 System Firmware Updating for Mac OS X OS X 10.3.9
After Installation Note A residual folder called "AppleInternal" will be created on your hard drive after you have installed the firmware update. Another folder, "PackageDataTools", is located within that folder. There is also an application called "Lurk-n-Launch" within that folder. You can safely delete this folder and its contents.