Hello Slitaz Gang,
I think I have found out what has been happening to some Slitaz 4.0 users, who are stuck at maximum 800x600 screen resolution. I have had the same problem with an IBM Aptiva, yet using the same PC, I'm able to get higher screen resolution with Slitaz 3.0. Without going into a long winded explanation as to how I found out, in Slitaz 4.0, THE XORG.CONF DefaultDepth STATEMENT IS BEING IGNORED. It is being handled correctly in Slitaz 3.0. I used the X server log (/var/log/Xorg.0.log) to see what was going on. For those who may be wondering why I'm talking about DefaultDepth, maximum screen resolution is determined using color depth (DefaultDepth) and the amount of video RAM. By specifying a lower color depth, like 16 instead of 24, more screen pixels can be contained by the available video RAM. In the posts that I saw complaining about the 800x600 problem, the posters didn't say anything about the hardware that they were using. I'll guess that they were using old low spec PCs with 2Mb of video RAM (like my Aptiva).
IBM Aptiva, 266MHz AMD K6-2, 256Mb memory, ATI Technologies Inc 3D Rage Pro AGP 1X with 2Mb video RAM (On motherboard)