Apple released MacBook and MacBook Pro EFI Firmware Update 2.0 late on Thursday. The firmware updates addressed an issue where external displays showed a purple cast.
MacBook EFI Firmware Update 2.0 requires the mid 2010 unibody MacBook and Mac OS X 10.6.5. The MacBook Pro EFI Firmware Update 2.0 requires the 13-inch MacBook Pro, also introduced in mid 2010, and Mac OS X 10.6.5.
Both firmware updates are available via the Software Update application, or as downloads at the Apple Support Web site.