According to Apple, the update addressed the following issues.
- Fixed a problem with incorrect rotation when working with video created by iPhone 3GS
- Resolved instability when adding multiple beat markers in some languages
- Corrected an issue where iMovie could become unresponsive after using fine-tuning controls beyond the stabilized portions of a clip
The update is recommended for all users of iMovie '09. iMovie 8.0.4 can be downloaded and installed by selecting Software Update from the Apple menu on your Finder desktop.