diff --git a/grub-core/loader/efi/fdt.c b/grub-core/loader/efi/fdt.c
index a18ca8ccb..ee9c5592c 100644
--- a/grub-core/loader/efi/fdt.c
+++ b/grub-core/loader/efi/fdt.c
@@ -66,7 +66,7 @@ grub_fdt_load (grub_size_t additional_size)
 
   if (raw_fdt)
     {
-      grub_memmove (fdt, raw_fdt, size);
+      grub_memmove (fdt, raw_fdt, size - additional_size);
       grub_fdt_set_totalsize (fdt, size);
     }
   else