diff --git a/Ymodem.cpp b/Ymodem.cpp
index d9603e7..742f51e 100644
--- a/Ymodem.cpp
+++ b/Ymodem.cpp
@@ -307,6 +307,7 @@ Ymodem::Code Ymodem::receivePacket()
     }
     else
     {
+      BOOST_LOG_TRIVIAL(debug) << "RET <= 0";
       return CodeNone;
     }
   }