diff --git a/grub-core/video/bitmap_scale.c b/grub-core/video/bitmap_scale.c
index 0b93d02..64bacbf 100644
--- a/grub-core/video/bitmap_scale.c
+++ b/grub-core/video/bitmap_scale.c
@@ -366,22 +366,31 @@ scale_nn (struct grub_video_bitmap *dst, struct grub_video_bitmap *src)
   /* bytes_per_pixel is the same for both src and dst. */
   unsigned bytes_per_pixel = dst->mode_info.bytes_per_pixel;
 
-  unsigned dy;
-  for (dy = 0; dy < dh; dy++)
+  unsigned dy, sy, ystep, yfrac, yover;
+  unsigned dx, sx, xstep, xfrac, xover;
+  ystep = sw / dw;
+  yover = sw % dw;
+  xstep = sh / dh;
+  xover = sh % dh;
+
+  for (dy = 0, sy = 0, yfrac = 0; dy < dh; dy++, sy += ystep, yfrac += yover)
     {
-      unsigned dx;
-      for (dx = 0; dx < dw; dx++)
+      if (yfrac > dw)
+	{
+	  yfrac -= dw;
+	  sy++;
+	}
+      for (dx = 0, sx = 0, xfrac = 0; dx < dw; dx++, sx += xstep, xfrac += xover)
         {
           grub_uint8_t *dptr;
           grub_uint8_t *sptr;
-          unsigned sx;
-          unsigned sy;
           unsigned comp;
 
-          /* Compute the source coordinate that the destination coordinate
-             maps to.  Note: sx/sw = dx/dw  =>  sx = sw*dx/dw. */
-          sx = sw * dx / dw;
-          sy = sh * dy / dh;
+	  if (xfrac > dh)
+	    {
+	      xfrac -= dh;
+	      sx++;
+	    }
 
           /* Get the address of the pixels in src and dst. */
           dptr = ddata + dy * dstride + dx * bytes_per_pixel;