diff --git a/drivers/auth/mbedtls/mbedtls_common.mk b/drivers/auth/mbedtls/mbedtls_common.mk
index 16ce65f..ae4b067 100644
--- a/drivers/auth/mbedtls/mbedtls_common.mk
+++ b/drivers/auth/mbedtls/mbedtls_common.mk
@@ -22,7 +22,7 @@
 MBEDTLS_SOURCES	+=		drivers/auth/mbedtls/mbedtls_common.c
 
 
-LIBMBEDTLS_SRCS		:= $(addprefix ${MBEDTLS_DIR}/library/,	\
+LIBMBEDTLS_SRCS		+= $(addprefix ${MBEDTLS_DIR}/library/,	\
 					aes.c 					\
 					asn1parse.c 				\
 					asn1write.c 				\