diff --git a/firmware/config/engines/test_engine.cpp b/firmware/config/engines/test_engine.cpp
index 9b18b246eb..667a043a30 100644
--- a/firmware/config/engines/test_engine.cpp
+++ b/firmware/config/engines/test_engine.cpp
@@ -5,6 +5,8 @@
  * VVT
  * set engine_type 45
  *
+ * See also custom_engine.cpp
+ *
  * @date Nov 14, 2014
  * @author Andrey Belomutskiy, (c) 2012-2017
  */