diff --git a/arch/arm/boards/at91sam9n12ek/init.c b/arch/arm/boards/at91sam9n12ek/init.c
index 310f418..2fe7a11 100644
--- a/arch/arm/boards/at91sam9n12ek/init.c
+++ b/arch/arm/boards/at91sam9n12ek/init.c
@@ -131,7 +131,7 @@
 static struct atmel_mci_platform_data mci0_data = {
 	.bus_width	= 4,
 	.detect_pin	= AT91_PIN_PA7,
-	.wp_pin		= 0,
+	.wp_pin		= -EINVAL,
 };
 
 static void ek_add_device_mci(void)