diff --git a/sys/arm/conf/SAM9260EK b/sys/arm/conf/SAM9260EK
index 53b293c699b..1edee77f99a 100644
--- a/sys/arm/conf/SAM9260EK
+++ b/sys/arm/conf/SAM9260EK
@@ -103,8 +103,10 @@ options 	PRINTF_BUFR_SIZE=128	# Prevent printf output being interspersed.
 #options 	BOOTP_NFSV3
 #options 	BOOTP_WIRED_TO=macb0
 
-# alternatively, boot from a MMC/SD memory card
-# s1 is FAT on this platform.
+# s3 because s1 is reserved for the DOS parittions sometimes needed to
+# boot off SD cards on the G20 and newer chips. s2 is reserved for
+# nanobsd's config partition. s3 and s4 are for the ping-pong upgrade
+# path. 9260 doesn't boot off SD, but let's keep things sane.
 options 	ROOTDEVNAME=\"ufs:/dev/mmcsd0s3a\"
 
 # Alternatively, boot from a USB card.
diff --git a/sys/arm/conf/SAM9G20EK b/sys/arm/conf/SAM9G20EK
index bd33e6bea05..685b2bf9a45 100644
--- a/sys/arm/conf/SAM9G20EK
+++ b/sys/arm/conf/SAM9G20EK
@@ -82,9 +82,11 @@ options 	DDB			# Enable the kernel debugger
 #options 	BOOTP_NFSV3
 #options 	BOOTP_WIRED_TO=ate0
 
-# s2 because s1 is reserved for the DOS parittions sometimes needed to
-# boot off SD cards on the G20 and newer chips.
-options 	ROOTDEVNAME=\"ufs:/dev/mmcsd0s2a\"
+# s3 because s1 is reserved for the DOS parittions sometimes needed to
+# boot off SD cards on the G20 and newer chips. s2 is reserved for
+# nanobsd's config partition. s3 and s4 are for the ping-pong upgrade
+# path.
+options 	ROOTDEVNAME=\"ufs:/dev/mmcsd0s3a\"
 
 # kernel/memory size reduction
 options 	MUTEX_NOINLINE