diff --git a/services/spd/tlkd/tlkd_main.c b/services/spd/tlkd/tlkd_main.c
index 2748868..948be5d 100644
--- a/services/spd/tlkd/tlkd_main.c
+++ b/services/spd/tlkd/tlkd_main.c
@@ -37,7 +37,7 @@
 /*******************************************************************************
  * CPU number on which TLK booted up
  ******************************************************************************/
-static int boot_cpu;
+static uint32_t boot_cpu;
 
 /* TLK UID: RFC-4122 compliant UUID (version-5, sha-1) */
 DEFINE_SVC_UUID(tlk_uuid,