Screen startup resolution not coming back

Yesterday, I put my MacBook in mirroring display with MiniDisplay to VGA adapter with 800x600 LCD Projector. It worked fine.

Today, I start up my MacBook, but the start up resolution screen still in 800x600 (not in native display). When the startup finished, (Get into logon screen) the resolution got back to native screen. 😮

Is there any setting I should change to reverse back my startup screen resolution? 😕 I've opened the display setting in system preference but there's no change at all.

Thanks, need fast reply since it's tickling my mind 😊