diff --git a/variants/arduino_zero/variant.cpp b/variants/arduino_zero/variant.cpp
index 7c8a805a70847a10ec4bd03559af321279188942..a5917a7b31be3923ea458c9a23f122205c546d02 100644
--- a/variants/arduino_zero/variant.cpp
+++ b/variants/arduino_zero/variant.cpp
@@ -169,8 +169,8 @@ const PinDescription g_APinDescription[]=
   // 35 .. 46 - EDBG
   // ----------------------
   // 35/36 - EDBG/UART
-  { PORTB, 22, PIO_SERCOM, PIN_ATTR_NONE, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER }, // TX: SERCOM5/PAD[2]
-  { PORTB, 23, PIO_SERCOM, PIN_ATTR_NONE, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER }, // RX: SERCOM5/PAD[3]
+  { PORTB, 22, PIO_SERCOM_ALT, PIN_ATTR_NONE, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER }, // TX: SERCOM5/PAD[2]
+  { PORTB, 23, PIO_SERCOM_ALT, PIN_ATTR_NONE, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER }, // RX: SERCOM5/PAD[3]
 
 	// 37/38 I2C (SDA/SCL and also EDBG:SDA/SCL)
   { PORTA, 22, PIO_SERCOM, PIN_ATTR_NONE, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER }, // SDA: SERCOM3/PAD[0]