I did it. From 10.6.0 to 10.6.6 in only 1 step, Notebookinstaller 0.8.5pre install, download 10.6.6 combo update, install, no restart but again Notebookinstaller 0.8.5pre, restart, very lazy boot with "like a dos screen", about 10min, reboot again, work. All the Settings were away, settings done.
Mirroring known issue, lines on the screen, MirrorDisplay.app installed, from Spotlight started, ok, problem with lines solved.
The only way to use an extended monitor is dell mini with 1024x600, 22" inch monitor with 1980x1020, but as a 2nd monitor.
Has anyone did the mirroring? If success, how ?