diff --git a/configs/samd20-xplained/include/board.h b/configs/samd20-xplained/include/board.h
index c7956e8ba23..78e30528b83 100644
--- a/configs/samd20-xplained/include/board.h
+++ b/configs/samd20-xplained/include/board.h
@@ -351,17 +351,19 @@
 #define BOARD_FLASH_WAITSTATES       1
 
 /* SERCOM definitions ***************************************************************/
-/* SERCOM4 is available on connectors EXT1 and EXT3
+/* SERCOM4 is available on connectors EXT1, EXT2, and EXT3
  *
- *   PIN   EXT1  EXT3  GPIO  Function
- *   ----  ---- ------ -----------
- *    13   PB09   PB13 SERCOM4 / USART RX
- *    14   PB08   PB12 SERCOM4 / USART TX
- *    19   19          GND
- *    20   20          VCC
+ *   PIN   EXT1 EXT2 EXT3 GPIO Function
+ *   ----  ---- ---- ---- ------------------
+ *    13   PB09 PB13 PB11 SERCOM4 / USART RX
+ *    14   PB08 PB12 PB12 SERCOM4 / USART TX
+ *    19   GND  GND  GND  N/A
+ *    20   VCC  VCC  VCC  N/A
  *
  * If you have a TTL to RS-232 converter then this is the most convenient
- * serial console to use.  It is the default in all of these configurations.
+ * serial console to use (because you don't lose the console device each time
+ * you lose the USB connection).  It is the default in all of the SAMD20
+ * configurations.
  */
 
 #define BOARD_SERCOM4_GCLKGEN        GCLK_CLKCTRL_GEN0