Apple today released iBook Audio Update 1.0, available only through the Software Update Control Panel. This update is only for iBooks released in May 2001.
According to information provided with the update, the iBook Audio Update improves the quality of sound output on Apple’s iBook (Dual USB) computers introduced in May 2001.
If you are using Mac OS X on your iBook, you must restart in Mac OS 9.1 to install the iBook Audio Update. Before installing the update Apple advises taking the following steps:
Make sure your iBook’s power cord is connected and plugged into a working power source.
Double-click the iBook Audio Update icon.
If a message says that this version of the iBook Audio Update will not run on this computer, then you do not need this update.
Follow the onscreen instructions. A status bar shows the progress of the update.
When a message says that iBook Audio Update has been successfully installed, click OK. Your iBook will restart.
The information also notes that if the message says the update was not completed successfully, to begin the update process again.