In the only game I have that uses that graphic mode,
Explora2, the display window is indeed 640200, but
there are two 320200 pictures that fill that area. The
text displayed is quite strange too
(RIS.......SOURIS.......SOU, in the attached screenshot).
As a side note, the game freezes just before being
playable (intro is ok, then the first place appears, and
the game freezes, and continues playing high pitched
sound (probably the last note of the intro music)).
It is still possible to close the window, then
to"EXIT:Closed the SDL Window, Press ENTER to
stop". No error msg is displayed.