diff --git a/config/boards/bananapim2.conf b/config/boards/bananapim2.conf
index c90794772d..9202de85f7 100644
--- a/config/boards/bananapim2.conf
+++ b/config/boards/bananapim2.conf
@@ -2,6 +2,7 @@
 BOARD_NAME="Banana Pi M2"
 LINUXFAMILY="sun6i"
 BOOTCONFIG="Sinovoip_BPI_M2_defconfig"
+OVERLAY_PREFIX="sun6i-a31s"
 #
 MODULES_NEXT="brcmfmac bonding"
 #
diff --git a/config/sources/sun6i.conf b/config/sources/sun6i.conf
index 45209e783d..9ec7ff547a 100644
--- a/config/sources/sun6i.conf
+++ b/config/sources/sun6i.conf
@@ -1,6 +1,9 @@
 
 source "${BASH_SOURCE%/*}/sunxi_common.inc"
 
+# though currently the only supported sun6i device is BPi M2
+# A31 and A31s have significant pinctrl differences so not setting OVERLAY_PREFIX here
+
 case $BRANCH in
 	dev)
 	KERNELSOURCE=$MAINLINE_KERNEL_SOURCE