diff --git a/polymer/eduke32/build/src/baselayer.c b/polymer/eduke32/build/src/baselayer.c
index 1d579c42c..26b33721b 100644
--- a/polymer/eduke32/build/src/baselayer.c
+++ b/polymer/eduke32/build/src/baselayer.c
@@ -328,8 +328,8 @@ int32_t baselayer_init(void)
     cvar_t cvars_engine[] =
     {
         { "r_usenewaspect","r_usenewaspect: enable/disable new screen aspect ratio determination code",(void *) &r_usenewaspect, CVAR_BOOL, 0, 1 },
-        { "r_screenaspect","r_screenaspect: if using the new aspect code and in fullscreen, screen aspect ratio in the form XXYY, e.g. 1609 for 16:9",
-          (void *) &r_screenxy, SCREENASPECT_CVAR_TYPE, 100, 9999 },
+        { "r_screenaspect","r_screenaspect: if using r_usenewaspect and in fullscreen, screen aspect ratio in the form XXYY, e.g. 1609 for 16:9",
+          (void *) &r_screenxy, SCREENASPECT_CVAR_TYPE, 0, 9999 },
         { "r_novoxmips","r_novoxmips: turn off/on the use of mipmaps when rendering 8-bit voxels",(void *) &novoxmips, CVAR_BOOL, 0, 1 },
         { "r_voxels","r_voxels: enable/disable automatic sprite->voxel rendering",(void *) &usevoxels, CVAR_BOOL, 0, 1 },
 #ifdef YAX_ENABLE
diff --git a/polymer/eduke32/build/src/config.c b/polymer/eduke32/build/src/config.c
index e08287fe7..151eebc43 100644
--- a/polymer/eduke32/build/src/config.c
+++ b/polymer/eduke32/build/src/config.c
@@ -401,7 +401,8 @@ int32_t writesetup(const char *fn)
              "; Use new aspect determination code? (classic/Polymost)\n"
              "r_usenewaspect = %d\n"
 #ifndef RENDERTYPEWIN
-             "; Screen aspect for fullscreen, in the form WWHH (e.g. 1609 for 16:9)\n"
+             "; Screen aspect for fullscreen, in the form WWHH (e.g. 1609 for 16:9).\n"
+             "; A value of 0 means to assume that the pixel aspect is square."
              "r_screenxy = %d\n"
 #endif
              "\n"
diff --git a/polymer/eduke32/build/src/engine.c b/polymer/eduke32/build/src/engine.c
index 17fd990f5..40c7d6018 100644
--- a/polymer/eduke32/build/src/engine.c
+++ b/polymer/eduke32/build/src/engine.c
@@ -117,7 +117,7 @@ static int32_t oxdimen = -1, oviewingrange = -1, oxyaspect = -1;
 
 // r_usenewaspect is the cvar, newaspect_enable to trigger the new behaviour in the code
 int32_t r_usenewaspect = 1, newaspect_enable=0;
-uint32_t r_screenxy = 403;  // 4:3 aspect ratio
+uint32_t r_screenxy = 0;
 
 int32_t curbrightness = 0, gammabrightness = 0;
 
@@ -13542,7 +13542,12 @@ void setaspect_new()
             int32_t pixratio;
 
             x=r_screenxy/100; y=r_screenxy%100;
-            if (y==0 || x==0) { x=4; y=3; }
+            if (y==0 || x==0)
+            {
+                // Assume square pixel aspect.
+                x = xdim;
+                y = ydim;
+            }
 
             pixratio = divscale16(xd*y, yd*x);
             yx = divscale16(yx, pixratio);