G9X / stock boards: Restricted minor recent change to G9X board

only, until more timing tests on stock board can be done.

In case you're wondering, I'm planning on using the PB7 back-light 
conection on an otherwise unmodified board, for those tests --
since PORTH isn't available and all. ;-)

src/pulses_avr.cpp

@@ -571,11 +571,11 @@ void setupPulsesDsm2()
 
   pulses2MHzWPtr -= 1; //remove last stopbits and
 
-//G: Removed to get waveform correct on analyser
-//_send_1(255); //prolong them
-
+#if !defined(GRUVIN9XPCB)
+//G: Removed to get waveform correct on analyser. Leave in for stock board until tests can be done.
   _send_1(0); //end of pulse stream
-
+#endif
+  
   pulses2MHzRPtr = pulses2MHz;
 }
 #endif