diff --git a/docs/grub.texi b/docs/grub.texi
index f8b4b3b21..f6c7f46b3 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -3036,16 +3036,18 @@ snapshot name is omitted.
 
 A block list is used for specifying a file that doesn't appear in the
 filesystem, like a chainloader. The syntax is
-@code{[@var{offset}]+@var{length}[,[@var{offset}]+@var{length}]@dots{}}.
+@code{[@var{offset}]+[@var{length}][,[@var{offset}]+[@var{length}]]@dots{}}.
 Here is an example:
 
 @example
-@code{0+100,200+1,300+300}
+@code{0+100,200+1,300+300,800+}
 @end example
 
 This represents that GRUB should read blocks 0 through 99, block 200,
-and blocks 300 through 599. If you omit an offset, then GRUB assumes
-the offset is zero.
+blocks 300 through 599, and blocks 800 until the end of the device.
+If you omit an offset, then GRUB assumes the offset is zero. If the
+length is omitted, then GRUB assumes the block list extends until the
+end of the device.
 
 Like the file name syntax (@pxref{File name syntax}), if a blocklist
 does not contain a device name, then GRUB uses GRUB's @dfn{root
diff --git a/grub-core/kern/fs.c b/grub-core/kern/fs.c
index c698295bc..e0d7e16a2 100644
--- a/grub-core/kern/fs.c
+++ b/grub-core/kern/fs.c
@@ -173,7 +173,11 @@ grub_fs_blocklist_open (grub_file_t file, const char *name)
 	}
 
       p++;
-      blocks[i].length = grub_strtoul (p, &p, 0);
+      if (*p == '\0' || *p == ',')
+        blocks[i].length = max_sectors - blocks[i].offset;
+      else
+        blocks[i].length = grub_strtoul (p, &p, 0);
+
       if (grub_errno != GRUB_ERR_NONE
 	  || blocks[i].length == 0
 	  || (*p && *p != ',' && ! grub_isspace (*p)))