I dont have a 770 any more so i cant test drive any changes but i might look into updating 770 version sometime soon. I think i looked for way to disable 'screen flash' but theres no settings for that in config files (only a command to cause a flash :/ ) But maybe i can find code to disable flashes and other items.

I think i remember on n800/2007 (where flicker was more common than on 2008) that it helped to have no windows loaded in background. You might also try increasing screensizemode to hide the status bar so those update wont possibly cause flash/flicker on repaints.