Why do most 32F769IDISCOVERY LCD examples display random pixels?

[CMumf.1]

I've been trying to get the (unmodified) example programs for the 32F769IDISCOVERY to draw anything on screen. LCD_DSI_CmdMode_DoubleBuffer works fine, but LCD_DSI_CmdMode_PartialRefresh, LCD_DSI_VideoMode_DoubleBuffering, and nearly all others just render random pixels to the screen. Once drawn the screen does not change - e.g. not a "snow" effect, just a static image. Am I doing something wrong?

[waclawek.jan]

> not a "snow" effect, just a static image

This might indicate problematic write to framebuffer. Is framebuffer in SDRAM? Try modifying the write timing in FMC.

I'm just speculating and don't know the primary reason, nor do I have this board. However, the DISCO boards do have revisions (check in the Disco's manual and/or HW design files/schematics), do use various chips (due to (un)availability), software does have shortcomings (eg. compiling using different version of compiler or optimization setting may reveal timing issues), STM32 do have errata and do have revisions fixing these errata...

JW