diff --git a/grub-core/osdep/windows/platform.c b/grub-core/osdep/windows/platform.c
index 912269191..7eb53fe01 100644
--- a/grub-core/osdep/windows/platform.c
+++ b/grub-core/osdep/windows/platform.c
@@ -201,7 +201,7 @@ set_efi_variable_bootn (grub_uint16_t n, void *in, grub_size_t len)
   set_efi_variable (varname, in, len);
 }
 
-void
+int
 grub_install_register_efi (grub_device_t efidir_grub_dev,
 			   const char *efifile_path,
 			   const char *efi_distributor)
@@ -363,7 +363,7 @@ grub_install_register_efi (grub_device_t efidir_grub_dev,
 	grub_util_error ("%s", grub_errmsg);
       efidir_grub_dev->disk->partition = p;
       grub_memcpy (hddp->partition_signature,
-		   gptdata.guid, 16);
+		   &gptdata.guid, 16);
 
       hddp->partmap_type = 2;
       hddp->signature_type = 2;
@@ -407,6 +407,8 @@ grub_install_register_efi (grub_device_t efidir_grub_dev,
 
   set_efi_variable_bootn (order_num, entry, (grub_uint8_t *) pathptr - entry);
   set_efi_variable (L"BootOrder", new_boot_order, new_boot_order_len * sizeof (grub_uint16_t));
+
+  return 0;
 }
 
 void