diff --git a/bl1/bl1_main.c b/bl1/bl1_main.c
index bff8d22..e11ead6 100644
--- a/bl1/bl1_main.c
+++ b/bl1/bl1_main.c
@@ -226,11 +226,11 @@
 /*******************************************************************************
  * Top level handler for servicing BL1 SMCs.
  ******************************************************************************/
-register_t bl1_smc_handler(unsigned int smc_fid,
-	register_t x1,
-	register_t x2,
-	register_t x3,
-	register_t x4,
+u_register_t bl1_smc_handler(unsigned int smc_fid,
+	u_register_t x1,
+	u_register_t x2,
+	u_register_t x3,
+	u_register_t x4,
 	void *cookie,
 	void *handle,
 	unsigned int flags)
@@ -269,12 +269,12 @@
  * BL1 SMC wrapper.  This function is only used in AArch32 mode to ensure ABI
  * compliance when invoking bl1_smc_handler.
  ******************************************************************************/
-register_t bl1_smc_wrapper(uint32_t smc_fid,
+u_register_t bl1_smc_wrapper(uint32_t smc_fid,
 	void *cookie,
 	void *handle,
 	unsigned int flags)
 {
-	register_t x1, x2, x3, x4;
+	u_register_t x1, x2, x3, x4;
 
 	assert(handle != NULL);