diff --git a/lib/trusted_os/trusted_os.c b/lib/trusted_os/trusted_os.c
index b24c3d3..ac6a681 100644
--- a/lib/trusted_os/trusted_os.c
+++ b/lib/trusted_os/trusted_os.c
@@ -14,7 +14,6 @@
 {
 	smc_args tos_uid_args = { SMC_TOS_UID };
 	smc_ret_values ret;
-	uint32_t *tos_uuid32;
 
 	ret = tftf_smc(&tos_uid_args);
 
@@ -23,11 +22,13 @@
 	     (ret.ret3 == 0)))
 		return 0;
 
-	tos_uuid32 = (uint32_t *) tos_uuid;
-	tos_uuid32[0] = ret.ret0;
-	tos_uuid32[1] = ret.ret1;
-	tos_uuid32[2] = ret.ret2;
-	tos_uuid32[3] = ret.ret3;
+	if (tos_uuid != NULL) {
+		uint32_t *tos_uuid32 = (uint32_t *) tos_uuid;
+		tos_uuid32[0] = ret.ret0;
+		tos_uuid32[1] = ret.ret1;
+		tos_uuid32[2] = ret.ret2;
+		tos_uuid32[3] = ret.ret3;
+	}
 
 	return 1;
 }