NYYRIKKI made a small 512x512 picture demo, see http://www.msx.org/forumtopicl7400.html
This displays nicely on a real MSX2, but is completely messed up on an openMSX MSX2... The demo is attached.
I retested it today. It's not garbled anymore, the image is good. Except that the top 16 (or so) lines are missing. They do show up on my real GT. Compare also to the image here: http://www.passionmsx.org/modules/mydownloads/singlefile.php?cid=67&lid=1084&lang=english openMSX doesn't show that very bright part at the top right anymore.
PS: the fix was in 12776.
I retested it today. It's not garbled anymore, the image is good. Except that the top 16 (or so) lines are missing. They do show up on my real GT. Compare also to the image here: http://www.passionmsx.org/modules/mydownloads/singlefile.php?cid=67&lid=1084&lang=english
openMSX doesn't show that very bright part at the top right anymore.
PS: the fix was in 12776.