[twobob]

Well I went off and found some c that blats stuff in and out of the buffer decently enough. for the 3 pictured)

perhaps a slightly less damn ugly eips alternative wouldnt actually go that far amiss...
tried messing with pgm. that might be a cheap alternative to real data?

dpavlin did a perl script that mangled pgm via perl back into native 4bit framebuffer.

might that be a useful touchstone? I gave it the once over.

so "pseudo cat pgm data" to fb0[susectionx][subsectiony] and update?

just spitballing, does actually sound very useful.