Barry mentioned the solution on the Developer Blog -
http://puppylinux.com/blog/?p=31#comment-126
He was referring to the Intel Classmate, but the fix should be the same for the Eee.BarryK wrote:I’ve got the standard Xvesa X server working at 800×480, that was easy — you need to go into /usr/X11R7/bin/xwin and bypass the ‘ddcprobe’ and just run the '915resolution 38 800 480' and set that as the only available resolution.
And once the i810 Xorg driver has been "fooled" into accepting 800x480 as a valid bios setting, Xorg should work as well.
There is also a good Developer Blog post about "Working with a small screen"
http://puppylinux.com/blog/?p=56#comments