diff --git a/Firmata.h b/Firmata.h
index fa0fa6c2..fb993d79 100644
--- a/Firmata.h
+++ b/Firmata.h
@@ -128,7 +128,7 @@ class FirmataClass
 
     /* private methods ------------------------------ */
     void strobeBlinkPin(byte pin, int count, int onInterval, int offInterval);
-    friend void FirmataMarshaller::encodeByteStream (size_t bytec, uint8_t * bytev, size_t max_bytes = 0) const;
+    friend void FirmataMarshaller::encodeByteStream (size_t bytec, uint8_t * bytev, size_t max_bytes) const;
 
     /* callback functions */
     static callbackFunction currentAnalogCallback;