diff --git a/hardware/arduino/avr/libraries/SoftwareSerial/SoftwareSerial.h b/hardware/arduino/avr/libraries/SoftwareSerial/SoftwareSerial.h
index e0e4746cd..27c0bfca9 100644
--- a/hardware/arduino/avr/libraries/SoftwareSerial/SoftwareSerial.h
+++ b/hardware/arduino/avr/libraries/SoftwareSerial/SoftwareSerial.h
@@ -88,7 +88,7 @@ public:
   void end();
   bool isListening() { return this == active_object; }
   bool stopListening();
-  bool overflow() { bool ret = _buffer_overflow; _buffer_overflow = false; return ret; }
+  bool overflow() { bool ret = _buffer_overflow; if (ret) _buffer_overflow = false; return ret; }
   int peek();
 
   virtual size_t write(uint8_t byte);