When using Mac OS 9.0.4 on some NuBus computers and non-PCI PowerBooks, display resolutions previously available may no longer appear in the Monitor Resolution control strip or Monitors control panel.
Solution
Install Video Extension 1.0, which can be downloaded from the Apple Software Updates Web site at http://www.apple.com/swupdates.
This Video Extension update restores access to all available resolutions with built-in video and video cards on NuBus computes and non-PCI PowerBooks.