Hi,
I can only say it always worked for me ;) Have you enabled the VGA BIOS hooks in SeaBIOS? Try with less RAM. I think I use 512MB, you can send me (in private please) your binary and I can flash it on Monday and see if I have same problems. I think it looks like something is wrong with video "bitrate" setup or something overlaps the gfx memory.
You can also try image from:
http://www.coreboot.org/ASUS_M2V-MX_SE
Thanks, Rudolf