diff --git a/library/debug.c b/library/debug.c
index a55324e..cf53667 100644
--- a/library/debug.c
+++ b/library/debug.c
@@ -355,7 +355,7 @@
             if( len > DEBUG_BUF_SIZE - 1 )
                 len = DEBUG_BUF_SIZE - 1;
 
-            memcpy( str, start, len );
+            mbedtls_platform_memcpy( str, start, len );
             str[len] = '\0';
 
             debug_send_line( ssl, level, file, line, str );