diff --git a/source/mbedtls_thread_config.h b/source/mbedtls_thread_config.h
index a23e25a..ad6acba 100644
--- a/source/mbedtls_thread_config.h
+++ b/source/mbedtls_thread_config.h
@@ -68,8 +68,6 @@
 #undef MBEDTLS_PK_WRITE_C
 #undef MBEDTLS_KEY_EXCHANGE_PSK_ENABLED
 #undef MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED
-#undef MBEDTLS_X509_CREATE_C
-#undef MBEDTLS_X509_CRT_WRITE_C
 */
 
 /* For TYPE_THREAD_BORDER_ROUTER */
@@ -83,9 +81,9 @@
 #define MBEDTLS_PK_WRITE_C
 #define MBEDTLS_KEY_EXCHANGE_PSK_ENABLED
 #define MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED
-#define MBEDTLS_X509_CREATE_C
-#define MBEDTLS_X509_CRT_WRITE_C
 
+#undef MBEDTLS_X509_CREATE_C
+#undef MBEDTLS_X509_CRT_WRITE_C
 #undef MBEDTLS_X509_CRL_PARSE_C
 #undef MBEDTLS_SSL_SERVER_NAME_INDICATION
 #undef MBEDTLS_SELF_TEST