Hi
I had the same issue with using grayscale VGA on the H7 a while ago. Seems the framebuffer architecture has been changed in a way that uses more memory now, which the H7 doesn’t have.
See details here: V4.8.1. breaking VGA on H7
And this is the commit with the changes I’ve implemented on my fork to fix it: Changed to fixed 1 byte/pixel framebuffer for H7 · falthaus/openmv@a004937 · GitHub
Maybe this helps
Felix