diff --git a/libraries/SPI/SPI.cpp b/libraries/SPI/SPI.cpp
index 335fbf0f94a1d8d846b37ede55bd77a189effe1b..2d428731a10ad61f571bdcd943cedc36f7d004e2 100644
--- a/libraries/SPI/SPI.cpp
+++ b/libraries/SPI/SPI.cpp
@@ -98,4 +98,4 @@ void SPIClass::detachInterrupt() {
 	// Should be disableInterrupt()
 }
 
-SPIClass SPI(&sercom4, 18, 20, 21);
+SPIClass SPI( &sercom4, PIN_SPI_MISO, PIN_SPI_SCK, PIN_SPI_MOSI ) ;
diff --git a/variants/arduino_zero/variant.cpp b/variants/arduino_zero/variant.cpp
index e17c8b4f877716426f5861988d3da4ebfa26464c..9c95365ad9382cd80530cae9b1ead3e4af80f4e6 100644
--- a/variants/arduino_zero/variant.cpp
+++ b/variants/arduino_zero/variant.cpp
@@ -207,5 +207,5 @@ SERCOM sercom3( SERCOM3 ) ;
 SERCOM sercom4( SERCOM4 ) ;
 SERCOM sercom5( SERCOM5 ) ;
 
-Uart Serial1( &sercom0, 0, 1 ) ;
-Uart Serial( &sercom5, 36, 35 ) ;
+Uart Serial1( &sercom0, PIN_SERIAL_RX, PIN_SERIAL_TX ) ;
+Uart Serial( &sercom5, PIN_SERIAL_RX, PIN_SERIAL_TX ) ;
diff --git a/variants/arduino_zero/variant.h b/variants/arduino_zero/variant.h
index 1466d2b643195bf529d512da58c18acba7f1ec24..d06622417b96fceb4db477def4d9006cd3733bf7 100644
--- a/variants/arduino_zero/variant.h
+++ b/variants/arduino_zero/variant.h
@@ -94,6 +94,17 @@ static const uint8_t A4  = PIN_A4 ;
 static const uint8_t A5  = PIN_A5 ;
 #define ADC_RESOLUTION		12
 
+/*
+ * Serial interfaces
+ */
+// Serial (EDBG)
+#define PIN_SERIAL_RX (31ul)
+#define PIN_SERIAL_TX (30ul)
+
+// Serial1
+#define PIN_SERIAL1_RX (0ul)
+#define PIN_SERIAL1_TX (1ul)
+
 /*
  * SPI Interfaces
  */
@@ -198,11 +209,11 @@ extern Uart Serial1;
 //
 // SERIAL_PORT_HARDWARE_OPEN  Hardware serial ports which are open for use.  Their RX & TX
 //                            pins are NOT connected to anything by default.
-#define SERIAL_PORT_MONITOR         Serial5
 #define SERIAL_PORT_USBVIRTUAL      SerialUSB
-#define SERIAL_PORT_HARDWARE_OPEN   Serial1
 #define SERIAL_PORT_HARDWARE        Serial
 #define SERIAL_PORT_HARDWARE1       Serial1
+#define SERIAL_PORT_MONITOR         SERIAL_PORT_HARDWARE
+#define SERIAL_PORT_HARDWARE_OPEN   SERIAL_PORT_HARDWARE1
 
 #endif /* _VARIANT_ARDUINO_ZERO_ */