diff --git a/postplug.d/30xorg b/postplug.d/30xorg
index 27768fe..9e6c476 100644
--- a/postplug.d/30xorg
+++ b/postplug.d/30xorg
@@ -435,7 +435,7 @@ warning: DDC hsync range cannot be detected, setting default of 30-49 kHz"
            HorizSync    30-49' $XORGCONF
       }
 
-      [ "$PANEL_SIZE_DETECTED" ] ||
+      [ "$HSYNC_RANGE_NOT_DETECTED" -a ! "$PANEL_SIZE_DETECTED" ] &&
          sed -i -e '/SubSection "Display"/a\
                Modes "1024x768" "800x600" "640x480"' $XORGCONF
    else