I use coreboot 4772 with SeaBIOS (the same is on SeaBIOS stable and new 1.7.3) I noticed bad display screen in VESA mode after restart WinXP OS (no ACPI). Bad screen is only after WinXP reboot in any program which use VESA mode e.g. coreboot logo, PLOP menu, PXElinux menu, Acronis Disk Director tool etc.
Bad display PXElinux menu: http://savepic.net/3961153.htm
This is original PNG 640x480 background my PXElinux menu: http://savepic.net/4031405.htm
If boot PC from PXElinux menu with menu.c32 (text mode) have no display problem.
If use vesamenu.c32 in pxelinux then have display problem.
This means that this is a problem VESA mode only.
Appear on the screen as if it was divided into sections the size of one character text about 4x12 pixels. My image size is 640x480. This means that screen size is 160x38 or 160x40 text character:
640 / 160 = 4
480 / 40 = 12