diff --git a/effects/uvmap/mainloop.asm b/effects/uvmap/mainloop.asm
index 023bc90b..3bd53c7d 100644
--- a/effects/uvmap/mainloop.asm
+++ b/effects/uvmap/mainloop.asm
@@ -7,7 +7,7 @@ group   macro                   ; cpu/bus cycles
         or.b    $4444(a2),\1    ; 12/3
         endm
 
-        movem.w d2-d7,-(sp)
+        movem.l d2-d7,-(sp)
 
         group   d0
         group   d1
@@ -20,4 +20,4 @@ group   macro                   ; cpu/bus cycles
         movem.w d0-d7,-(a0)     ; 8+4*8/8
                                 ; 13.25/3.25 per pixel
 
-        movem.w (sp)+,d2-d7
+        movem.l (sp)+,d2-d7
diff --git a/effects/uvmap/uvmap.c b/effects/uvmap/uvmap.c
index b4b22c2d..0b30fa28 100644
--- a/effects/uvmap/uvmap.c
+++ b/effects/uvmap/uvmap.c
@@ -67,7 +67,7 @@ static void MakeUVMapRenderCode(void) {
    * [a b c d e f g h] => [a b e f c d g h] */
   short n = WIDTH * HEIGHT / 32;
 
-  *code++ = 0x48a7; *code++ = 0x3f00; /* movem.w d2-d7,-(sp) */
+  *code++ = 0x48e7; *code++ = 0x3f00; /* movem.l d2-d7,-(sp) */
 
   while (n--) {
     short m;
@@ -87,7 +87,7 @@ static void MakeUVMapRenderCode(void) {
     *code++ = 0x48a0; *code++ = 0xff00; /* d0-d7,-(a0) */
   }
 
-  *code++ = 0x4c9f; *code++ = 0x00fc; /* movem.w (sp)+,d2-d7 */
+  *code++ = 0x4cdf; *code++ = 0x00fc; /* movem.l (sp)+,d2-d7 */
   *code++ = 0x4e75; /* rts */
 }
 
diff --git a/tools/pylib/uvmap.py b/tools/pylib/uvmap.py
index 75dcaab8..e6ce8500 100644
--- a/tools/pylib/uvmap.py
+++ b/tools/pylib/uvmap.py
@@ -121,10 +121,11 @@ def save(self, name, fn=None, scale=256):
             print('  %s,' % ', '.join(row))
         print('};')
 
-    def save_uv(self, name):
+    def save_uv(self, name, scale=256):
+        size = self.texsize
         im = Image.new('L', (self.width, self.height))
-        im.putdata([frpart(u) * 256 for u in self.umap])
+        im.putdata([int(frpart(u) * scale) % size for u in self.umap])
         im.save(name + '-u.png', 'PNG')
         im = Image.new('L', (self.width, self.height))
-        im.putdata([frpart(v) * 256 for v in self.vmap])
+        im.putdata([int(frpart(v) * scale) % size for v in self.vmap])
         im.save(name + '-v.png', 'PNG')