diff --git a/configs/config-mini-tls1_1.h b/configs/config-mini-tls1_1.h
index 9092829..78e31d5 100644
--- a/configs/config-mini-tls1_1.h
+++ b/configs/config-mini-tls1_1.h
@@ -82,4 +82,9 @@
 #endif
 #include "mbedtls/check_config.h"
 
+/* Error messages and TLS debugging traces
+ * (huge code size increase, needed for tests/ssl-opt.sh) */
+//#define MBEDTLS_DEBUG_C
+//#define MBEDTLS_ERROR_C
+
 #endif /* MBEDTLS_CONFIG_H */