diff --git a/drivers/auth/auth_mod.c b/drivers/auth/auth_mod.c
index 1cea60b..eb537b6 100644
--- a/drivers/auth/auth_mod.c
+++ b/drivers/auth/auth_mod.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -30,7 +30,7 @@
 
 /* Pointer to CoT */
 extern const auth_img_desc_t *const cot_desc_ptr;
-extern unsigned int auth_img_flags[];
+extern unsigned int auth_img_flags[MAX_NUMBER_IDS];
 
 static int cmp_auth_param_type_desc(const auth_param_type_desc_t *a,
 		const auth_param_type_desc_t *b)