Mega 2560 with ST7920 LCD and u8glib problem

A "display module" usually has a reset circuit included. Often "COG (Chip On Glass) Displays" do not have such a circuit. Then: Some controllers do need a reset circuit other do not need that circuit. At the end i have only seen one display which really needs a good reset (PCF8812). So i do not think its a reset issue.

Oliver