diff --git a/radio/src/opentx.cpp b/radio/src/opentx.cpp
index 5e5df5655..6c9ccda1e 100644
--- a/radio/src/opentx.cpp
+++ b/radio/src/opentx.cpp
@@ -2592,7 +2592,7 @@ void opentxInit(OPENTX_INIT_ARGS)
 
   startPulses();
 
-  wdt_enable(WDT_500MS);
+  wdt_enable(WDTO_500MS);
 }
 
 #if defined(SIMU)
diff --git a/radio/src/opentx.h b/radio/src/opentx.h
index 373d4eecc..570c67772 100644
--- a/radio/src/opentx.h
+++ b/radio/src/opentx.h
@@ -1756,6 +1756,4 @@ extern JitterMeter<uint16_t> avgJitter[NUMBER_ANALOG];
 #endif
 #endif
 
-#define WDT_500MS 500
-
 #endif // _OPENTX_H_
diff --git a/radio/src/targets/common/avr/serial_driver.cpp b/radio/src/targets/common/avr/serial_driver.cpp
index d9625fd08..6602fd890 100644
--- a/radio/src/targets/common/avr/serial_driver.cpp
+++ b/radio/src/targets/common/avr/serial_driver.cpp
@@ -1,23 +1,23 @@
-/*
- * Copyright (C) OpenTX
- *
- * Based on code named
- *   th9x - http://code.google.com/p/th9x 
- *   er9x - http://code.google.com/p/er9x
- *   gruvin9x - http://code.google.com/p/gruvin9x
- *
- * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
-
+/*
+ * Copyright (C) OpenTX
+ *
+ * Based on code named
+ *   th9x - http://code.google.com/p/th9x 
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
 #include "serial_driver.h"
 #include "opentx.h"
 
@@ -292,8 +292,12 @@ void SERIAL_Init(void) {
 	// set 8N1
 	UCSR0B = 0 | (0 << RXCIE0) | (0 << TXCIE0) | (0 << UDRIE0) | (0 << RXEN0) | (0 << TXEN0) | (0 << UCSZ02);
 	UCSR0C = 0 | (1 << UCSZ01) | (1 << UCSZ00);
-	while (UCSR0A & (1 << RXC0))
-	  UDR0; // flush receive buffer
+
+#if !defined(SIMU)
+        while (UCSR0A & (1 << RXC0)) {
+          UDR0; // flush receive buffer
+        }
+#endif
 
 	SERIAL_EnableTXD();
 	SERIAL_EnableRXD();
diff --git a/radio/src/targets/horus/board.h b/radio/src/targets/horus/board.h
index 73bb4d7fa..a44dd4264 100644
--- a/radio/src/targets/horus/board.h
+++ b/radio/src/targets/horus/board.h
@@ -175,6 +175,7 @@ extern uint32_t rotencSpeed;
 void checkRotaryEncoder(void);
 
 // WDT driver
+#define WDTO_500MS                            500
 #define wdt_disable()
 void watchdogInit(unsigned int duration);
 #if defined(WATCHDOG_DISABLED) || defined(SIMU)
diff --git a/radio/src/targets/taranis/board.h b/radio/src/targets/taranis/board.h
index 9f89427b8..45d1b65d8 100644
--- a/radio/src/targets/taranis/board.h
+++ b/radio/src/targets/taranis/board.h
@@ -234,6 +234,7 @@ void checkRotaryEncoder(void);
 #endif
 
 // WDT driver
+#define WDTO_500MS                            500
 #if defined(WATCHDOG_DISABLED) || defined(SIMU)
   #define wdt_enable(x)
   #define wdt_reset()