diff --git a/target/linux/ramips/mt7621/base-files/lib/upgrade/inteno.sh b/target/linux/ramips/mt7621/base-files/lib/upgrade/inteno.sh
index 677000f6b1a..ecaa1a808c5 100644
--- a/target/linux/ramips/mt7621/base-files/lib/upgrade/inteno.sh
+++ b/target/linux/ramips/mt7621/base-files/lib/upgrade/inteno.sh
@@ -17,15 +17,8 @@
 . /lib/upgrade/nand.sh
 
 inteno_do_upgrade () {
-	local tar_file=$1
-	local cmd=cat
-	# WARNING: This fails if tar contains more than one 'sysupgrade-*' directory.
-	local board_dir="$(tar tf "$tar_file" | grep -m 1 '^sysupgrade-.*/$')"
-	board_dir="${board_dir%/}"
-	tar -xaf "$tar_file"
-
 	# get the size of the new bootfs
-	local _bootfs_size=$(wc -c < "$board_dir/kernel")
+	local _bootfs_size=$(tar -tvf $1 | grep kernel | awk '{print $3}')
 	[ -n "$_bootfs_size" -a "$_bootfs_size" -gt "0" ] || nand_do_upgrade_failed
 
 	# remove existing rootfses and recreate rootfs_0
@@ -35,15 +28,11 @@ inteno_do_upgrade () {
 	ubirmvol /dev/ubi0 --name=rootfs_data > /dev/null 2>&1
 	ubimkvol /dev/ubi0 --type=static --size=${_bootfs_size} --name=rootfs_0
 
-	# update the rootfs_0 contents
-	local _kern_ubivol=$( nand_find_volume "ubi0" "rootfs_0" )
-	ubiupdatevol "/dev/$_kern_ubivol" "$board_dir/kernel"
-
 	fw_setenv root_vol rootfs_0
 	fw_setenv boot_cnt_primary 0
 	fw_setenv boot_cnt_alt 0
 
 	# proceed to upgrade the default way
-	CI_KERNPART=none
+	CI_KERNPART=rootfs_0
 	nand_do_upgrade "$1"
 }