--- a/arch/arm/mach-at91/board-foxg20.c	2011-11-10 17:43:26.264928133 +0100
+++ b/arch/arm/mach-at91/board-foxg20.c	2011-11-26 00:35:36.025571017 +0100
@@ -88,11 +88,15 @@ static void __init foxg20_init_early(voi
 		ATMEL_UART_CTS
 		| ATMEL_UART_RTS);
 
+#ifdef CONFIG_SAM9G20_UART4
 	/* USART4 on ttyS5. (Rx & Tx only) */
 	at91_register_uart(AT91SAM9260_ID_US4, 5, 0);
+#endif
 
+#ifdef CONFIG_SAM9G20_UART5
 	/* USART5 on ttyS6. (Rx & Tx only) */
 	at91_register_uart(AT91SAM9260_ID_US5, 6, 0);
+#endif
 
 	/* set serial console to ttyS0 (ie, DBGU) */
 	at91_set_serial_console(0);
--- a/arch/arm/mach-at91/Kconfig	2011-11-10 19:20:40.153061249 +0100
+++ b/arch/arm/mach-at91/Kconfig	2011-11-28 16:43:51.024905442 +0100
@@ -507,6 +507,18 @@
 
 endif
 
+config SAM9G20_UART4
+	bool "serial port UART4"
+	help
+	  This will use PA30,31 and will probably be /dev/ttyS5
+
+config SAM9G20_UART5
+	bool "serial port UART5"
+	help
+	  This will use PB12,13 and will probably be /dev/ttyS6 if
+	  SAM9G20_UART4 selected, otherwise it will probably
+	  be /dev/ttyS5
+
 endif
 
 choice