diff --git a/grub-core/video/fb/fbutil.c b/grub-core/video/fb/fbutil.c
index b98bb51fe..25ef39f47 100644
--- a/grub-core/video/fb/fbutil.c
+++ b/grub-core/video/fb/fbutil.c
@@ -67,7 +67,7 @@ get_pixel (struct grub_video_fbblit_info *source,
     case 1:
       if (source->mode_info->blit_format == GRUB_VIDEO_BLIT_FORMAT_1BIT_PACKED)
         {
-          int bit_index = y * source->mode_info->width + x;
+          grub_uint64_t bit_index = (grub_uint64_t) y * source->mode_info->width + x;
           grub_uint8_t *ptr = source->data + bit_index / 8;
           int bit_pos = 7 - bit_index % 8;
           color = (*ptr >> bit_pos) & 0x01;
@@ -138,7 +138,7 @@ set_pixel (struct grub_video_fbblit_info *source,
     case 1:
       if (source->mode_info->blit_format == GRUB_VIDEO_BLIT_FORMAT_1BIT_PACKED)
         {
-          int bit_index = y * source->mode_info->width + x;
+          grub_uint64_t bit_index = (grub_uint64_t) y * source->mode_info->width + x;
           grub_uint8_t *ptr = source->data + bit_index / 8;
           int bit_pos = 7 - bit_index % 8;
           *ptr = (*ptr & ~(1 << bit_pos)) | ((color & 0x01) << bit_pos);
diff --git a/include/grub/fbutil.h b/include/grub/fbutil.h
index 4205eb917..78a1ab3b4 100644
--- a/include/grub/fbutil.h
+++ b/include/grub/fbutil.h
@@ -31,14 +31,19 @@ struct grub_video_fbblit_info
   grub_uint8_t *data;
 };
 
-/* Don't use for 1-bit bitmaps, addressing needs to be done at the bit level
-   and it doesn't make sense, in general, to ask for a pointer
-   to a particular pixel's data.  */
+/*
+ * Don't use for 1-bit bitmaps, addressing needs to be done at the bit level
+ * and it doesn't make sense, in general, to ask for a pointer
+ * to a particular pixel's data.
+ *
+ * This function assumes that bounds checking has been done in previous phase
+ * and they are opted out in here.
+ */
 static inline void *
 grub_video_fb_get_video_ptr (struct grub_video_fbblit_info *source,
               unsigned int x, unsigned int y)
 {
-  return source->data + y * source->mode_info->pitch + x * source->mode_info->bytes_per_pixel;
+  return source->data + (grub_addr_t) y * source->mode_info->pitch + (grub_addr_t) x * source->mode_info->bytes_per_pixel;
 }
 
 /* Advance pointer by VAL bytes. If there is no unaligned access available,