Index: /trunk/src/VBox/Devices/Graphics/DevVGA.cpp
===================================================================
--- /trunk/src/VBox/Devices/Graphics/DevVGA.cpp	(revision 37646)
+++ /trunk/src/VBox/Devices/Graphics/DevVGA.cpp	(revision 37647)
@@ -714,4 +714,5 @@
         if (s->fRealRetrace)
             vga_update_retrace_state(s);
+        s->st00 = (s->st00 & ~0x10) | (0x90 >> ((val >> 2) & 0x3));
         break;
     case 0x3c4: