diff --git a/package/base-files/files/lib/functions/system.sh b/package/base-files/files/lib/functions/system.sh
index 46311ae0c..a5456594f 100644
--- a/package/base-files/files/lib/functions/system.sh
+++ b/package/base-files/files/lib/functions/system.sh
@@ -172,6 +172,14 @@ macaddr_add() {
 	echo $oui:$nic
 }
 
+macaddr_generate_from_mmc_cid() {
+	local mmc_dev=$1
+
+	local sd_hash=$(sha256sum /sys/class/block/$mmc_dev/device/cid)
+	local mac_base=$(macaddr_canonicalize "$(echo "${sd_hash}" | dd bs=1 count=12 2>/dev/null)")
+	echo "$(macaddr_unsetbit_mc "$(macaddr_setbit_la "${mac_base}")")"
+}
+
 macaddr_geteui() {
 	local mac=$1
 	local sep=$2
diff --git a/target/linux/rockchip/armv8/base-files/etc/board.d/02_network b/target/linux/rockchip/armv8/base-files/etc/board.d/02_network
index 17ce0ac3b..f383c2da1 100755
--- a/target/linux/rockchip/armv8/base-files/etc/board.d/02_network
+++ b/target/linux/rockchip/armv8/base-files/etc/board.d/02_network
@@ -46,13 +46,6 @@ rockchip_setup_interfaces()
 	esac
 }
 
-generate_mac_from_mmc_cid()
-{
-	local sd_hash=$(sha256sum /sys/class/block/mmcblk*/device/cid | head -n 1)
-	local mac_base=$(macaddr_canonicalize "$(echo "${sd_hash}" | dd bs=1 count=12 2>/dev/null)")
-	echo "$(macaddr_unsetbit_mc "$(macaddr_setbit_la "${mac_base}")")"
-}
-
 nanopi_r4s_get_mac()
 {
 	local interface=$1
@@ -65,7 +58,7 @@ nanopi_r4s_get_mac()
 			address=$(macaddr_setbit_la "$address")
 		fi
 	else
-		address=$(generate_mac_from_mmc_cid)
+		address=$(macaddr_generate_from_mmc_cid mmcblk1)
 		if [ "$interface" = "lan" ]; then
 			address=$(macaddr_add "$address" 1)
 		fi
@@ -99,7 +92,7 @@ rockchip_setup_macs()
 	sharevdi,h3399pc|\
 	sharevdi,guangmiao-g4c|\
 	rocktech,mpc1903)
-		wan_mac=$(generate_mac_from_mmc_cid)
+		wan_mac=$(macaddr_generate_from_mmc_cid mmcblk0)
 		lan_mac=$(macaddr_add "$wan_mac" +1)
 		;;
 	friendlyarm,nanopi-r4s|\