diff --git a/board/phytium/common/busybox_initrd_overlay/etc/inittab b/board/phytium/common/busybox_initrd_overlay/etc/inittab
new file mode 100644
index 00000000..431ce8e9
--- /dev/null
+++ b/board/phytium/common/busybox_initrd_overlay/etc/inittab
@@ -0,0 +1,41 @@
+# /etc/inittab
+#
+# Copyright (C) 2001 Erik Andersen <andersen@codepoet.org>
+#
+# Note: BusyBox init doesn't support runlevels.  The runlevels field is
+# completely ignored by BusyBox init. If you want runlevels, use
+# sysvinit.
+#
+# Format for each entry: <id>:<runlevels>:<action>:<process>
+#
+# id        == tty to run on, or empty for /dev/console
+# runlevels == ignored
+# action    == one of sysinit, respawn, askfirst, wait, and once
+# process   == program to run
+
+# Startup the system
+::sysinit:/bin/mount -o remount,rw /
+::sysinit:/bin/mkdir -p /dev/pts /dev/shm
+::sysinit:/bin/mount -a
+::sysinit:/sbin/swapon -a
+null::sysinit:/bin/ln -sf /proc/self/fd /dev/fd
+null::sysinit:/bin/ln -sf /proc/self/fd/0 /dev/stdin
+null::sysinit:/bin/ln -sf /proc/self/fd/1 /dev/stdout
+null::sysinit:/bin/ln -sf /proc/self/fd/2 /dev/stderr
+::sysinit:/bin/hostname -F /etc/hostname
+# now run any rc scripts
+::sysinit:/etc/init.d/rcS
+
+# Put a getty on the serial port
+#ttyS0::respawn:/sbin/getty -L ttyS0 115200 vt100 # GENERIC_SERIAL
+ttyAMA0::respawn:/sbin/getty -L ttyAMA0 115200 vt100
+ttyAMA1::respawn:/sbin/getty -L ttyAMA1 115200 vt100
+tty1::respawn:/sbin/getty 38400 tty1 
+
+# Stuff to do for the 3-finger salute
+#::ctrlaltdel:/sbin/reboot
+
+# Stuff to do before rebooting
+::shutdown:/etc/init.d/rcK
+::shutdown:/sbin/swapoff -a
+::shutdown:/bin/umount -a -r
diff --git a/board/phytium/common/busybox_initrd_overlay/init b/board/phytium/common/busybox_initrd_overlay/init
new file mode 100755
index 00000000..62977750
--- /dev/null
+++ b/board/phytium/common/busybox_initrd_overlay/init
@@ -0,0 +1,163 @@
+#!/bin/sh 
+# Copyright (C) 2011 O.S. Systems Software LTDA.
+# Licensed on MIT
+#
+# Provides the API to be used by the initramfs modules
+#
+# Modules need to provide the following functions:
+#
+# <module>_enabled : check if the module ought to run (return 1 to skip)
+# <module>_run     : do what is need
+#
+# Boot parameters are available on environment in the as:
+#
+# 'foo=value' as 'bootparam_foo=value'
+# 'foo' as 'bootparam_foo=true'
+# 'foo.bar[=value] as 'foo_bar=[value|true]'
+
+# Register a function to be called before running a module
+# The hook is called as:
+#   <function> pre <module>
+add_module_pre_hook() {
+	MODULE_PRE_HOOKS="$MODULE_PRE_HOOKS $1"
+}
+
+# Register a function to be called after running a module
+# The hook is called as:
+#   <function> post <module>
+add_module_post_hook() {
+	MODULE_POST_HOOKS="$MODULE_POST_HOOKS $1"
+}
+
+# Load kernel module
+load_kernel_module() {
+	if modprobe $1 >/dev/null 2>&1; then
+		info "Loaded module $1"
+	else
+		debug "Failed to load module $1"
+	fi
+}
+
+# Prints information
+msg() {
+	echo "$@" >/dev/console
+}
+
+# Prints information if verbose bootparam is used
+info() {
+	[ -n "$bootparam_verbose" ] && echo "$@" >/dev/console
+}
+
+# Prints information if debug bootparam is used
+debug() {
+	[ -n "$bootparam_debug" ] && echo "DEBUG: $@" >/dev/console
+}
+
+# Prints a message and start a endless loop
+fatal() {
+    echo $1 >/dev/console
+    echo >/dev/console
+
+    if [ -n "$bootparam_init_fatal_sh" ]; then
+        sh
+    else
+	while [ "true" ]; do
+		sleep 3600
+	done
+    fi
+}
+
+# Variables shared amoung modules
+ROOTFS_DIR="/rootfs" # where to do the switch root
+MODULE_PRE_HOOKS=""  # functions to call before running each module
+MODULE_POST_HOOKS="" # functions to call after running each module
+MODULES_DIR=/init.d  # place to look for modules
+EFI_DIR=/sys/firmware/efi  # place to store device firmware information
+
+# make mount stop complaining about missing /etc/fstab
+touch /etc/fstab
+
+# initialize /proc, /sys, /run/lock and /var/lock
+mkdir -p /proc /sys /run/lock /var/lock
+mount -t proc proc /proc
+mount -t sysfs sysfs /sys
+
+if [ -d $EFI_DIR ];then
+	mount -t efivarfs none /sys/firmware/efi/efivars
+fi
+
+# populate bootparam environment
+for p in `cat /proc/cmdline`; do
+	if [ -n "$quoted" ]; then
+		value="$value $p"
+		if [ "`echo $p | sed -e 's/\"$//'`" != "$p" ]; then
+			eval "bootparam_${quoted}=${value}"
+			unset quoted
+		fi
+		continue
+	fi
+
+	opt=`echo $p | cut -d'=' -f1`
+	opt=`echo $opt | sed -e 'y/.-/__/'`
+	if [ "`echo $p | cut -d'=' -f1`" = "$p" ]; then
+		eval "bootparam_${opt}=true"
+	else
+		value="`echo $p | cut -d'=' -f2-`"
+		if [ "`echo $value | sed -e 's/^\"//'`" != "$value" ]; then
+			quoted=${opt}
+			continue
+		fi
+		eval "bootparam_${opt}=\"${value}\""
+	fi
+done
+
+# use /dev with devtmpfs
+if grep -q devtmpfs /proc/filesystems; then
+	mkdir -p /dev
+	mount -t devtmpfs devtmpfs /dev
+else
+	if [ ! -d /dev ]; then
+		fatal "ERROR: /dev doesn't exist and kernel doesn't has devtmpfs enabled."
+	fi
+fi
+
+mkdir $ROOTFS_DIR
+
+# Load and run modules
+for m in $MODULES_DIR/*; do
+	# Skip backup files
+	if [ "`echo $m | sed -e 's/\~$//'`" != "$m" ]; then
+		continue
+	fi
+
+	module=`basename $m | cut -d'-' -f 2`
+	debug "Loading module $module"
+
+	# pre hooks
+	for h in $MODULE_PRE_HOOKS; do
+		debug "Calling module hook (pre): $h"
+		eval "$h pre $module"
+		debug "Finished module hook (pre): $h"
+	done
+
+	# process module
+	. $m
+
+	if ! eval "${module}_enabled"; then
+		debug "Skipping module $module"
+		continue
+	fi
+
+	debug "Running ${module}_run"
+	eval "${module}_run"
+
+	# post hooks
+	for h in $MODULE_POST_HOOKS; do
+		debug "Calling module hook (post): $h"
+		eval "$h post $module"
+		debug "Finished module hook (post): $h"
+	done
+done
+
+# Catch all
+fatal "ERROR: Initramfs failed to initialize the system."
diff --git a/board/phytium/common/busybox_initrd_overlay/init.d/01-udev b/board/phytium/common/busybox_initrd_overlay/init.d/01-udev
new file mode 100755
index 00000000..4898b892
--- /dev/null
+++ b/board/phytium/common/busybox_initrd_overlay/init.d/01-udev
@@ -0,0 +1,50 @@
+#!/bin/sh
+# Copyright (C) 2011, 2012 O.S. Systems Software LTDA.
+# Licensed on MIT
+
+udev_shutdown_hook_handler() {
+	status=$1
+	module=$2
+	if [ "$status" = "pre" ] && [ "$module" = "finish" ]; then
+		udevadm settle
+		killall `basename $_UDEV_DAEMON` 2>/dev/null
+	fi
+}
+
+udev_daemon() {
+	OPTIONS="/sbin/udev/udevd /sbin/udevd /lib/udev/udevd /lib/systemd/systemd-udevd"
+
+	for o in $OPTIONS; do
+		if [ -x "$o" ]; then
+			echo $o
+			return 0
+		fi
+	done
+
+	return 1
+}
+
+_UDEV_DAEMON=`udev_daemon`
+
+udev_enabled() {
+	if [ -z "$_UDEV_DAEMON" ]; then
+		msg "WARNING: Cannot find the udev daemon; daemon will not be started in initramfs."
+		return 1
+	fi
+
+	return 0
+}
+
+udev_run() {
+	add_module_pre_hook "udev_shutdown_hook_handler"
+
+	mkdir -p /run
+	mkdir -p /var/run
+
+	# Workaround if console=null, systemd-udevd needs valid stdin, stdout and stderr to work
+	sh -c "exec 4< /dev/console" || { exec 0> /dev/null; exec 1> /dev/null; exec 2> /dev/null; }
+
+	$_UDEV_DAEMON --daemon
+	udevadm trigger --action=add
+	udevadm settle
+}
diff --git a/board/phytium/common/busybox_initrd_overlay/init.d/90-rootfs b/board/phytium/common/busybox_initrd_overlay/init.d/90-rootfs
new file mode 100755
index 00000000..10b95831
--- /dev/null
+++ b/board/phytium/common/busybox_initrd_overlay/init.d/90-rootfs
@@ -0,0 +1,66 @@
+#!/bin/sh
+# Copyright (C) 2011 O.S. Systems Software LTDA.
+# Licensed on MIT
+
+rootfs_enabled() {
+	return 0
+}
+
+rootfs_run() {
+        if [ -z "$ROOTFS_DIR" ]; then
+		return
+        fi
+	C=0
+	delay=${bootparam_rootdelay:-1}
+	timeout=${bootparam_roottimeout:-5}
+	while ! mountpoint -q $ROOTFS_DIR; do
+		if [ $(( $C * $delay )) -gt $timeout ]; then
+			fatal "root '$bootparam_root' doesn't exist or does not contain a /dev."
+		fi
+
+		if [ -n "$bootparam_root" ]; then
+			debug "No e2fs compatible filesystem has been mounted, mounting $bootparam_root..."
+
+			if [ "`echo ${bootparam_root} | cut -c1-5`" = "UUID=" ]; then
+				root_uuid=`echo $bootparam_root | cut -c6-`
+				bootparam_root="/dev/disk/by-uuid/$root_uuid"
+			elif [ "`echo ${bootparam_root} | cut -c1-9`" = "PARTUUID=" ]; then
+				root_partuuid=`echo $bootparam_root | cut -c10-`
+				bootparam_root="/dev/disk/by-partuuid/$root_partuuid"
+			elif [ "`echo ${bootparam_root} | cut -c1-10`" = "PARTLABEL=" ]; then
+				root_partlabel=`echo $bootparam_root | cut -c11-`
+				bootparam_root="/dev/disk/by-partlabel/$root_partlabel"
+			elif [ "`echo ${bootparam_root} | cut -c1-6`" = "LABEL=" ]; then
+				root_label=`echo $bootparam_root | cut -c7-`
+				bootparam_root="/dev/disk/by-label/$root_label"
+			fi
+
+			if [ -e "$bootparam_root" ]; then
+				flags=""
+				if [ -n "$bootparam_ro" ] && ! echo "$bootparam_rootflags" | grep -w -q "ro"; then
+					if [  -n "$bootparam_rootflags" ]; then
+						bootparam_rootflags="$bootparam_rootflags,"
+					fi
+					bootparam_rootflags="${bootparam_rootflags}ro"
+				fi
+				if [ -n "$bootparam_rootflags" ]; then
+					flags="$flags -o$bootparam_rootflags"
+				fi
+				if [ -n "$bootparam_rootfstype" ]; then
+					flags="$flags -t$bootparam_rootfstype"
+				fi
+				mount $flags $bootparam_root $ROOTFS_DIR
+				if mountpoint -q $ROOTFS_DIR; then
+					break
+				else
+					# It is unlikely to change, but keep trying anyway.
+					# Perhaps we pick a different device next time.
+					umount $ROOTFS_DIR
+					fi
+				fi
+		fi
+		debug "Sleeping for $delay second(s) to wait root to settle..."
+		sleep $delay
+		C=$(( $C + 1 ))
+	done
+}
diff --git a/board/phytium/common/busybox_initrd_overlay/init.d/99-finish b/board/phytium/common/busybox_initrd_overlay/init.d/99-finish
new file mode 100755
index 00000000..866bb1cc
--- /dev/null
+++ b/board/phytium/common/busybox_initrd_overlay/init.d/99-finish
@@ -0,0 +1,28 @@
+#!/bin/sh
+# Copyright (C) 2011 O.S. Systems Software LTDA.
+# Licensed on MIT
+
+finish_enabled() {
+	return 0
+}
+
+finish_run() {
+	if [ -n "$ROOTFS_DIR" ]; then
+		if [ ! -d $ROOTFS_DIR/dev ]; then
+			fatal "ERROR: There's no '/dev' on rootfs."
+		fi
+
+		info "Switching root to '$ROOTFS_DIR'..."
+
+		debug "Moving /dev, /proc and /sys onto rootfs..."
+	
+		mount --move /dev $ROOTFS_DIR/dev
+		#mount --move /proc $ROOTFS_DIR/proc
+		mount --move /sys $ROOTFS_DIR/sys
+
+		cd $ROOTFS_DIR
+		exec switch_root -c /dev/console $ROOTFS_DIR ${bootparam_init:-/sbin/init}
+	else
+		debug "No rootfs has been set"
+	fi
+}
diff --git a/board/phytium/common/debian-archive-bullseye-stable.gpg b/board/phytium/common/debian-archive-bullseye-stable.gpg
new file mode 100644
index 00000000..8ecabc7d
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diff --git a/board/phytium/common/debian-package-installer b/board/phytium/common/debian-package-installer
new file mode 100755
index 00000000..c193ec68
--- /dev/null
+++ b/board/phytium/common/debian-package-installer
@@ -0,0 +1,116 @@
+#!/bin/bash
+
+DISTROTYPE=$3
+DISTROSCALE=$5
+tarch=$1
+
+do_distrorfs_second_stage() {
+    [ -f /etc/buildinfo -a ! -f /proc/uptime ] && return
+    packages_list=/usr/aptpkg/$4
+    . $packages_list
+
+    echo "1." $1
+    echo "2." $2
+    echo "3." $3
+    echo "4." $4
+    echo "5." $5
+    echo "6." $6
+    if [ ! -d /home/user ]; then
+    	useradd -m -d /home/user -s /bin/bash user
+    	gpasswd -a user sudo
+    	echo -e 'root\nroot\n' | passwd root
+    	echo -e 'user\nuser\n' | passwd user
+    	usermod -aG sudo user
+	chown -R user:user /home/user
+    fi
+    if [ -d /etc/shadow ]; then
+	cd /etc
+	chmod u=rw,g=r,o=r shadow
+    fi
+    # set default hostname
+    echo localhost > /etc/hostname
+
+    # set apt sources list to install additional packages
+    asl=/etc/apt/sources.list
+    rm -f $asl
+    cat <<-EOF > $asl
+	deb http://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye main contrib non-free
+	deb http://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-updates main contrib non-free
+	deb http://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-backports main contrib non-free
+	deb http://mirrors.tuna.tsinghua.edu.cn/debian-security bullseye-security main contrib non-free
+	EOF
+    chmod +777 /tmp
+    apt update
+    DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C \
+    apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" update || exit 1
+
+    DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C \
+    apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" upgrade || exit 1
+    echo upgraded
+
+    export LC_ALL=C LANGUAGE=C LANG=C
+
+    echo installing base packages: $pkglist
+    for pkg in $additional_base_packages_list; do
+	echo Installing $pkg ...
+	DEBIAN_FRONTEND=noninteractive apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" install $pkg || exit 1
+    done
+
+    dpkg -l | grep linux-headers | cut -d ' ' -f3 | xargs dpkg --purge
+    dpkg -l | grep linux-kbuild | cut -d ' ' -f3 | xargs dpkg --purge
+
+    echo installed additional packages.
+    if [ $6 = desktop ]; then
+	for pkg in task-xfce-desktop ukui-greeter; do
+                DEBIAN_FRONTEND=noninteractive apt -y install $pkg || true
+	done
+	usermod -a -G video,render,audio user
+
+	ln -sf /lib/systemd/system/lightdm.service /etc/systemd/system/display-manager.service
+	sed -i "s/gdm3/lightdm/" /etc/X11/default-display-manager
+	echo '[SeatDefaults]'  >> /etc/lightdm/lightdm.conf
+	echo 'greeter-session=ukui-greeter'  >> /etc/lightdm/lightdm.conf
+	echo 'user-session=xfce'  >> /etc/lightdm/lightdm.conf
+
+    fi
+
+    # clean cached packages
+    apt-get clean
+
+
+    if [ $1 = arm64 ]; then
+	sysarch=aarch64-linux-gnu
+    elif [ $1 = armhf ]; then
+	sysarch=arm-linux-gnueabihf
+    fi
+
+
+    [ -f /usr/bin/sudo -a ! -u /usr/bin/sudo ] && chmod +s /usr/bin/sudo
+    [ -d /var/cache/man ] && chown -R man:root /var/cache/man
+    [ -d /var/lib/sddm ] && chown -R sddm:sddm /var/lib/sddm
+
+    # some shared libraries locate in /lib/aarch64-linux-gnu(or /lib/arm-linux-gnueabihf) and /usr/local/lib
+    echo export LD_LIBRARY_PATH=/usr/local/lib:/usr/lib/$sysarch:/lib/$sysarch >> /etc/profile
+
+    tmpusr=`ls -t /home | cut -d' ' -f1 | head -1`
+    [ -d /home/$tmpusr -a "$tmpusr" != "user" ] && rm -rf /home/$tmpusr
+
+    test -c /dev/pts/0 && umount /dev/pts
+    test -f /proc/uptime && umount /proc
+
+    echo APT Packages List: > /etc/packages.list
+    echo -e "Package\t Version\t Download-Size\t APT-Sources" >> /etc/packages.list
+    apt list --installed | cut  -d/ -f1 | xargs apt show | \
+	grep -E '^Package:|^APT-Sources:|^Version:|^Download-Size:'  > packagelist
+    lnum=`wc -l packagelist |cut -d' ' -f1`
+    for((i=1; i<$lnum;)); do
+	t=$[ $i + 3 ]
+	sed -n "${i},${t}p"  packagelist | grep -E 'Package:|APT-Sources:|Version:|Download-Size:' | \
+	tr "\n" " "  | cut -d' ' -f2,4,6,7,9,10 >> /etc/packages.list
+	i=$[ $i + 4 ]
+    done
+    rm -f packagelist
+}
+
+do_distrorfs_second_stage $1 $2 $3 $4 $5 $6
+# end second stage installing
diff --git a/board/phytium/common/linux-4.19/scripts/basic/fixdep b/board/phytium/common/linux-4.19/scripts/basic/fixdep
new file mode 100755
index 00000000..e88975ce
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diff --git a/board/phytium/common/linux-4.19/scripts/genksyms/genksyms b/board/phytium/common/linux-4.19/scripts/genksyms/genksyms
new file mode 100755
index 00000000..fc7af3df
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diff --git a/board/phytium/common/linux-4.19/scripts/mod/modpost b/board/phytium/common/linux-4.19/scripts/mod/modpost
new file mode 100755
index 00000000..b4a97962
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diff --git a/board/phytium/common/linux-5.10/scripts/basic/fixdep b/board/phytium/common/linux-5.10/scripts/basic/fixdep
new file mode 100755
index 00000000..5285f284
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diff --git a/board/phytium/common/linux-5.10/scripts/mod/modpost b/board/phytium/common/linux-5.10/scripts/mod/modpost
new file mode 100755
index 00000000..7ddfbabc
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diff --git a/board/phytium/common/post-build.sh b/board/phytium/common/post-build.sh
new file mode 100755
index 00000000..d62a9c75
--- /dev/null
+++ b/board/phytium/common/post-build.sh
@@ -0,0 +1,124 @@
+#!/usr/bin/env bash
+
+deploy_kernel_headers_510 () {
+	topdir=$(pwd)
+	pdir=$1
+	version=$2
+	srctree=$pdir/lib/modules/$version/source
+	objtree=$pdir/lib/modules/$version/build
+	cd $objtree
+	mkdir debian
+
+	(
+		cd $srctree
+		find . arch/arm64 -maxdepth 1 -name Makefile\*
+		find include scripts -type f -o -type l
+		find arch/arm64 -name Kbuild.platforms -o -name Platform
+		find $(find arch/arm64 -name include -o -name scripts -type d) -type f
+	) > debian/hdrsrcfiles
+
+	{
+		if grep -q "^CONFIG_STACK_VALIDATION=y" include/config/auto.conf; then
+			echo tools/objtool/objtool
+		fi
+
+		find arch/arm64/include Module.symvers include scripts -type f
+
+		if grep -q "^CONFIG_GCC_PLUGINS=y" include/config/auto.conf; then
+			find scripts/gcc-plugins -name \*.so
+		fi
+	} > debian/hdrobjfiles
+
+	destdir=$pdir/usr/src/linux-headers-$version
+	mkdir -p $destdir
+	tar -c -f - -C $srctree -T debian/hdrsrcfiles | tar -xf - -C $destdir
+	tar -c -f - -T debian/hdrobjfiles | tar -xf - -C $destdir
+	rm -rf debian
+
+	# copy .config manually to be where it's expected to be
+	cp .config $destdir/.config
+	# used to build dma
+	cp drivers/dma/dmaengine.h $1/usr/include
+	cp drivers/dma/virt-dma.h $1/usr/include
+	find $destdir -name "*.o" -type f -exec rm -rf {} \;
+	cd $topdir
+	cp -r board/phytium/common/linux-5.10/scripts $destdir
+
+	rm -rf $srctree
+	rm -rf $objtree
+	ln -s /usr/src/linux-headers-$version $pdir/lib/modules/$version/build
+}
+
+deploy_kernel_headers_419 () {
+	topdir=$(pwd)
+	pdir=$1
+	version=$2
+	srctree=$pdir/lib/modules/$version/source
+	objtree=$pdir/lib/modules/$version/build
+	cd $objtree
+	mkdir debian
+
+	(cd $srctree; find . -name Makefile\* -o -name Kconfig\* -o -name \*.pl) > "$objtree/debian/hdrsrcfiles"
+	(cd $srctree; find arch/*/include include scripts -type f -o -type l) >> "$objtree/debian/hdrsrcfiles"
+	(cd $srctree; find arch/arm64 -name module.lds -o -name Kbuild.platforms -o -name Platform) >> "$objtree/debian/hdrsrcfiles"
+	(cd $srctree; find $(find arch/arm64 -name include -o -name scripts -type d) -type f) >> "$objtree/debian/hdrsrcfiles"
+	if grep -q '^CONFIG_STACK_VALIDATION=y' .config ; then
+		(cd $objtree; find tools/objtool -type f -executable) >> "$objtree/debian/hdrobjfiles"
+	fi
+	(cd $objtree; find arch/arm64/include Module.symvers include scripts -type f) >> "$objtree/debian/hdrobjfiles"
+	if grep -q '^CONFIG_GCC_PLUGINS=y' .config ; then
+		(cd $objtree; find scripts/gcc-plugins -name \*.so -o -name gcc-common.h) >> "$objtree/debian/hdrobjfiles"
+	fi
+	destdir=$pdir/usr/src/linux-headers-$version
+	mkdir -p "$destdir"
+	(cd $srctree; tar -c -f - -T -) < "$objtree/debian/hdrsrcfiles" | (cd $destdir; tar -xf -)
+	(cd $objtree; tar -c -f - -T -) < "$objtree/debian/hdrobjfiles" | (cd $destdir; tar -xf -)
+	(cd $objtree; cp .config $destdir/.config) # copy .config manually to be where it's expected to be
+	(cd $srctree; cp --parents tools/include/tools/be_byteshift.h $destdir)
+	(cd $srctree; cp --parents tools/include/tools/le_byteshift.h $destdir)
+	(cd $srctree; cp drivers/dma/dmaengine.h $1/usr/include) # used to build dma
+	(cd $srctree; cp drivers/dma/virt-dma.h $1/usr/include)
+	find $destdir -name "*.o" -type f -exec rm -rf {} \;
+	cd $topdir
+	cp -r board/phytium/common/linux-4.19/scripts $destdir
+	rm -rf "$objtree/debian"
+
+	rm -rf $srctree
+	rm -rf $objtree
+	ln -sf "/usr/src/linux-headers-$version" "$pdir/lib/modules/$version/build"
+}
+
+main()
+{
+	# $1 - the current rootfs directory, skeleton-custom or target
+
+	if [ ! -d $1/lib/modules ]; then
+		make linux-rebuild ${O:+O=$O}
+	fi
+
+	KERNELVERSION=`ls $1/lib/modules`
+	if grep -Eq "^BR2_ROOTFS_LINUX_HEADERS=y$" ${BR2_CONFIG} && [ -L $1/lib/modules/${KERNELVERSION}/source ]; then
+		if [[ ${KERNELVERSION} = 5.10* || ${KERNELVERSION} = 5.15* ]];then
+			deploy_kernel_headers_510 $1 ${KERNELVERSION}
+		elif [[ ${KERNELVERSION} = 4.19* ]];then
+			deploy_kernel_headers_419 $1 ${KERNELVERSION}
+		else
+			echo "error: linux kernel version is not 4.19, 5.10, or 5.15."
+		fi
+	fi
+
+	if grep -Eq "^BR2_ROOTFS_CHOWN=y$" ${BR2_CONFIG}; then
+		sudo chroot ${1} systemctl enable systemd-rootfs-chown.service
+	fi
+
+	if grep -Eq "^BR2_PACKAGE_PHYTIUM_OPTEE=y$" ${BR2_CONFIG}; then
+		# add tee-supplicant systemd service
+		cp -dpf package/phytium-optee/phytium-tee-supplicant.service $1/lib/systemd/system/phytium-tee-supplicant.service
+		# default set start tee-supplicant
+		ln -sf /lib/systemd/system/phytium-tee-supplicant.service $1/etc/systemd/system/sysinit.target.wants/phytium-tee-supplicant.service
+	fi
+
+	exit $?
+}
+
+main $@
diff --git a/board/phytium/common/post-custom-skeleton-debian-11.sh b/board/phytium/common/post-custom-skeleton-debian-11.sh
new file mode 100755
index 00000000..c1ad5dd5
--- /dev/null
+++ b/board/phytium/common/post-custom-skeleton-debian-11.sh
@@ -0,0 +1,207 @@
+#!/usr/bin/env bash
+
+distro=bullseye
+
+trap recover_from_ctrl_c INT
+
+recover_from_ctrl_c()
+{
+	do_recover_from_error "Interrupt caught ... exiting"
+	exit 1
+}
+
+do_recover_from_error()
+{
+	sudo chroot $RFSDIR /bin/umount /proc > /dev/null 2>&1;
+	sudo chroot $RFSDIR /bin/umount /sys > /dev/null 2>&1;
+	USER=$(id -u); GROUPS=${GROUPS}; \
+	sudo chroot $RFSDIR  /bin/chown -R ${USER}:${GROUPS} / > /dev/null 2>&1;
+	echo -e "\n************"
+    echo $1
+	echo -e "  Please running the below commands before re-compiling:"
+	echo -e "    rm -rf $RFSDIR"
+	echo -e "    make skeleton-custom-dirclean"
+	echo -e "  Or\n    make skeleton-custom-dirclean O=<output dir>"
+}
+
+do_distrorfs_first_stage() {
+# $1: platform architecture, arm64
+# $2: rootfs directory, output/build/skeleton-custom
+# $3: board/phytium/common/ubuntu-additional_packages_list
+# $4: bullseye
+# $5: debian
+# $6: plat name
+# $7: desktop or base
+
+    DISTROTYPE=$5
+    [ -z "$RFSDIR" ] && RFSDIR=$2
+    [ -z $RFSDIR ] && echo No RootFS exist! && return
+    [ -f $RFSDIR/etc/.firststagedone ] && echo $RFSDIR firststage exist! && return
+    [ -f /etc/.firststagedone -a ! -f /proc/uptime ] && return
+
+    if [ $1 = arm64 ]; then
+	tgtarch=aarch64
+    elif [ $1 = armhf ]; then
+	tgtarch=arm
+    fi
+
+    qemu-${tgtarch}-static -version > /dev/null 2>&1
+    if [ "x$?" != "x0" ]; then
+        echo qemu-${tgtarch}-static not found
+        exit 1
+    fi
+
+    debootstrap --version > /dev/null 2>&1
+    if [ "x$?" != "x0" ]; then
+        echo debootstrap not found
+        exit 1
+    fi
+
+    sudo chown 0:0  $RFSDIR
+    sudo mkdir -p $2/usr/local/bin
+    sudo cp -f board/phytium/common/debian-package-installer $RFSDIR/usr/local/bin/
+    packages_list=board/phytium/common/$3
+    [ ! -f $packages_list ] && echo $packages_list not found! && exit 1
+
+    echo additional packages list: $packages_list
+    if [ ! -d $RFSDIR/usr/aptpkg ]; then
+	sudo mkdir -p $RFSDIR/usr/aptpkg
+	sudo cp -f $packages_list $RFSDIR/usr/aptpkg
+    fi
+
+    sudo mkdir -p $RFSDIR/etc
+    sudo cp -f /etc/resolv.conf $RFSDIR/etc/resolv.conf
+
+    if [ ! -d $RFSDIR/debootstrap ]; then
+        echo "testdeboot"
+	export LANG=en_US.UTF-8
+	sudo debootstrap --keyring=board/phytium/common/debian-archive-bullseye-stable.gpg --arch=$1 --foreign bullseye $RFSDIR  https://mirrors.tuna.tsinghua.edu.cn/debian/
+
+	[ $1 != amd64 -a ! -f $RFSDIR/usr/bin/qemu-${tgtarch}-static ] && sudo cp $(which qemu-${tgtarch}-static) $RFSDIR/usr/bin
+	echo "installing for second-stage ..."
+	DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C \
+	sudo chroot $RFSDIR /debootstrap/debootstrap  --variant=minbase --second-stage
+	if [ "x$?" != "x0" ]; then
+		do_recover_from_error "debootstrap failed in second-stage"
+		exit 1
+	fi
+
+	echo "configure ... "
+	DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C \
+	sudo chroot $RFSDIR dpkg --configure -a
+    fi
+
+    sudo chroot $RFSDIR debian-package-installer $1 $distro $5 $3 $6 $7
+	if [ "x$?" != "x0" ]; then
+		 do_recover_from_error "debian-package-installer failed"
+		exit 1
+	fi
+
+    # sudo chroot $RFSDIR systemctl enable systemd-rootfs-resize
+    file_s=$(sudo find $RFSDIR -perm -4000)
+    sudo chown -R $USER:$GROUPS $RFSDIR
+    for f in $file_s; do
+        sudo chmod u+s $f
+    done
+    sudo chmod u+s $RFSDIR/sbin/unix_chkpwd
+
+    if [ $distro = bullseye ]; then
+	echo debian,11 | tee $RFSDIR/etc/.firststagedone 1>/dev/null
+    elif [ $distro = bionic ]; then
+	echo Ubuntu,18.04.5 | tee $RFSDIR/etc/.firststagedone 1>/dev/null
+    fi
+    setup_distribution_info $5 $2 $1
+
+    #rm $RFSDIR/etc/apt/apt.conf
+    sudo rm $RFSDIR/dev/* -rf
+}
+
+setup_distribution_info () {
+    DISTROTYPE=$1
+    RFSDIR=$2
+    tarch=$3
+    distroname=`head -1 $RFSDIR/etc/.firststagedone | cut -d, -f1`
+    distroversion=`head -1 $RFSDIR/etc/.firststagedone | cut -d, -f2`
+    releaseversion="$distroname (based on $DISTROTYPE-$distroversion-base) ${tarch}"
+    releasestamp="Build: `date +'%Y-%m-%d %H:%M:%S'`"
+    echo $releaseversion > $RFSDIR/etc/buildinfo
+    sed -i "1 a\\$releasestamp" $RFSDIR/etc/buildinfo
+    if grep U-Boot $RFSDIR/etc/.firststagedone 1>$RFSDIR/dev/null 2>&1; then
+        tail -1 $RFSDIR/etc/.firststagedone >> $RFSDIR/etc/buildinfo
+    fi
+
+    if [ $DISTROTYPE = ubuntu ]; then
+        echo $distroname $1-$distroversion > $RFSDIR/etc/issue
+        echo $distroname $1-$distroversion > $RFSDIR/etc/issue.net
+
+        tgtfile=$RFSDIR/etc/lsb-release
+        echo DISTRIB_ID=Phytium > $tgtfile
+        echo DISTRIB_RELEASE=$distroversion >> $tgtfile
+        echo DISTRIB_CODENAME=$distro >> $tgtfile
+        echo DISTRIB_DESCRIPTION=\"$distroname $1-$distroversion\" >> $tgtfile
+
+        tgtfile=$RFSDIR/etc/update-motd.d/00-header
+        echo '#!/bin/sh' > $tgtfile
+        echo '[ -r /etc/lsb-release ] && . /etc/lsb-release' >> $tgtfile
+        echo 'printf "Welcome to %s (%s %s %s)\n" "$DISTRIB_DESCRIPTION" "$(uname -o)" "$(uname -r)" "$(uname -m)"' >> $tgtfile
+
+        tgtfile=$RFSDIR/etc/update-motd.d/10-help-text
+        echo '#!/bin/sh' > $tgtfile
+        echo 'printf "\n"' >> $tgtfile
+        echo 'printf " * Support:        https://www.phytium.com.cn\n"' >> $tgtfile
+
+        tgtfile=$RFSDIR/usr/lib/os-release
+        echo NAME=\"$distroname\" > $tgtfile
+        echo VERSION=${DISTROTYPE}-$distroversion >> $tgtfile
+        echo ID=debian >> $tgtfile
+        echo VERSION_ID=$distroversion >> $tgtfile
+        echo PRETTY_NAME=\"Ubuntu Built with Buildroot, based on Ubuntu $distroversion LTS\" >> $tgtfile
+        echo VERSION_CODENAME=$distro >> $tgtfile
+
+        rm -f $RFSDIR/etc/default/motd-news
+        rm -f $RFSDIR/etc/update-motd.d/50-motd-news
+    fi
+}
+
+plat_name()
+{
+	echo "phytium"
+}
+
+arch_type()
+{
+	if grep -Eq "^BR2_aarch64=y$" ${BR2_CONFIG}; then
+		echo "arm64"
+	elif grep -Eq "^BR2_arm=y$" ${BR2_CONFIG}; then
+		echo "armhf"
+	fi
+}
+
+full_rtf()
+{
+	if grep -Eq "^BR2_PACKAGE_ROOTFS_DESKTOP=y$" ${BR2_CONFIG}; then
+		echo "desktop"
+	else
+		echo "base"
+	fi
+}
+
+main()
+{
+	# $1 - the current rootfs directory, skeleton-custom or target
+	rm -rf $1/*
+
+	# run first stage do_distrorfs_first_stage arm64 ${1} ubuntu-additional_packages_list bullseye debian
+	do_distrorfs_first_stage $(arch_type) ${1} ubuntu-additional_packages_list bullseye debian $(plat_name) $(full_rtf)
+
+	# change the hostname to "platforms-Ubuntu"
+	echo $(plat_name)-debian > ${1}/etc/hostname
+
+	if ! grep -q  "$(plat_name)-debian"  ${1}/etc/hosts; then
+		echo 127.0.0.1   $(plat_name)-debian | sudo tee -a ${1}/etc/hosts 1>/dev/null
+	fi
+
+	exit $?
+}
+
+main $@
diff --git a/board/phytium/common/post-custom-skeleton-ubuntu.sh b/board/phytium/common/post-custom-skeleton-ubuntu.sh
new file mode 100755
index 00000000..26414115
--- /dev/null
+++ b/board/phytium/common/post-custom-skeleton-ubuntu.sh
@@ -0,0 +1,217 @@
+#!/usr/bin/env bash
+
+trap recover_from_ctrl_c INT
+
+recover_from_ctrl_c()
+{
+	do_recover_from_error "Interrupt caught ... exiting"
+	exit 1
+}
+
+do_recover_from_error()
+{
+	sudo chroot $RFSDIR /bin/umount /proc > /dev/null 2>&1;
+	sudo chroot $RFSDIR /bin/umount /sys > /dev/null 2>&1;
+	USER=$(id -u); GROUPS=${GROUPS}; \
+	sudo chroot $RFSDIR  /bin/chown -R ${USER}:${GROUPS} / > /dev/null 2>&1;
+	echo -e "\n************"
+    echo $1
+	echo -e "  Please running the below commands before re-compiling:"
+	echo -e "    rm -rf $RFSDIR"
+	echo -e "    make skeleton-custom-dirclean"
+	echo -e "  Or\n    make skeleton-custom-dirclean O=<output dir>"
+}
+
+do_distrorfs_first_stage() {
+# $1: platform architecture, arm64
+# $2: rootfs directory, output/build/skeleton-custom
+# $3: board/phytium/common/ubuntu-additional_packages_list
+# $4: focal
+# $5: ubuntu
+# $6: plat name
+# $7: desktop or base
+
+    DISTROTYPE=$5
+    [ -z "$RFSDIR" ] && RFSDIR=$2
+    [ -z $RFSDIR ] && echo No RootFS exist! && return
+    [ -f $RFSDIR/etc/.firststagedone ] && echo $RFSDIR firststage exist! && return
+    [ -f /etc/.firststagedone -a ! -f /proc/uptime ] && return
+
+    if [ $1 = arm64 ]; then
+	tgtarch=aarch64
+    elif [ $1 = armhf ]; then
+	tgtarch=arm
+    fi
+
+    qemu-${tgtarch}-static -version > /dev/null 2>&1
+    if [ "x$?" != "x0" ]; then
+        echo qemu-${tgtarch}-static not found
+        exit 1
+    fi
+
+    debootstrap --version > /dev/null 2>&1
+    if [ "x$?" != "x0" ]; then
+        echo debootstrap not found
+        exit 1
+    fi
+
+    sudo chown 0:0 $RFSDIR
+    sudo mkdir -p $2/usr/local/bin
+    sudo cp -f board/phytium/common/ubuntu-package-installer $RFSDIR/usr/local/bin/
+    packages_list=board/phytium/common/$3
+    [ ! -f $packages_list ] && echo $packages_list not found! && exit 1
+
+    echo additional packages list: $packages_list
+    if [ ! -d $RFSDIR/usr/aptpkg ]; then
+	sudo mkdir -p $RFSDIR/usr/aptpkg
+	sudo cp -f $packages_list $RFSDIR/usr/aptpkg
+    fi
+
+    sudo mkdir -p $RFSDIR/etc
+    sudo cp -f /etc/resolv.conf $RFSDIR/etc/resolv.conf
+
+    if [ ! -d $RFSDIR/debootstrap ]; then
+        echo "testdeboot"
+	export LANG=en_US.UTF-8
+	sudo debootstrap --arch=$1 --foreign $4 $RFSDIR  https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports
+
+	[ $1 != amd64 -a ! -f $RFSDIR/usr/bin/qemu-${tgtarch}-static ] && sudo cp $(which qemu-${tgtarch}-static) $RFSDIR/usr/bin
+	echo "installing for second-stage ..."
+	DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C \
+	sudo chroot $RFSDIR /debootstrap/debootstrap  --second-stage
+	if [ "x$?" != "x0" ]; then
+		do_recover_from_error "debootstrap failed in second-stage"
+		exit 1
+	fi
+
+	echo "configure ... "
+	DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C \
+	sudo chroot $RFSDIR dpkg --configure -a
+    fi
+
+    sudo chroot $RFSDIR ubuntu-package-installer $1 $4 $5 $3 $6 $7
+	if [ "x$?" != "x0" ]; then
+		 do_recover_from_error "ubuntu-package-installer failed"
+		exit 1
+	fi
+
+    # sudo chroot $RFSDIR systemctl enable systemd-rootfs-resize
+    file_s=$(sudo find $RFSDIR -perm -4000)
+    sudo chown -R $USER:$GROUPS $RFSDIR
+    for f in $file_s; do
+        sudo chmod u+s $f
+    done
+    sudo chmod u+s $RFSDIR/sbin/unix_chkpwd
+ 
+    if dpkg-query -l snapd | grep ii 1>/dev/null; then
+        chmod +rw -R $RFSDIR/var/lib/snapd/
+    fi
+
+    if [ $4 = focal ]; then
+	echo Ubuntu,20.04 | tee $RFSDIR/etc/.firststagedone 1>/dev/null
+    elif [ $4 = jammy ]; then
+	echo Ubuntu,22.04 | tee $RFSDIR/etc/.firststagedone 1>/dev/null
+    fi
+    setup_distribution_info $5 $2 $1 $4
+
+    #rm $RFSDIR/etc/apt/apt.conf
+    rm $RFSDIR/dev/* -rf
+}
+
+setup_distribution_info () {
+    DISTROTYPE=$1
+    RFSDIR=$2
+    tarch=$3
+    distro=$4
+    distroname=`head -1 $RFSDIR/etc/.firststagedone | cut -d, -f1`
+    distroversion=`head -1 $RFSDIR/etc/.firststagedone | cut -d, -f2`
+    releaseversion="$distroname (based on $DISTROTYPE-$distroversion-base) ${tarch}"
+    releasestamp="Build: `date +'%Y-%m-%d %H:%M:%S'`"
+    echo $releaseversion > $RFSDIR/etc/buildinfo
+    sed -i "1 a\\$releasestamp" $RFSDIR/etc/buildinfo
+    if grep U-Boot $RFSDIR/etc/.firststagedone 1>$RFSDIR/dev/null 2>&1; then
+        tail -1 $RFSDIR/etc/.firststagedone >> $RFSDIR/etc/buildinfo
+    fi
+
+    if [ $DISTROTYPE = ubuntu ]; then
+        echo $distroname $1-$distroversion > $RFSDIR/etc/issue
+        echo $distroname $1-$distroversion > $RFSDIR/etc/issue.net
+
+        tgtfile=$RFSDIR/etc/lsb-release
+        echo DISTRIB_ID=Phytium > $tgtfile
+        echo DISTRIB_RELEASE=$distroversion >> $tgtfile
+        echo DISTRIB_CODENAME=$distro >> $tgtfile
+        echo DISTRIB_DESCRIPTION=\"$distroname $1-$distroversion\" >> $tgtfile
+
+        tgtfile=$RFSDIR/etc/update-motd.d/00-header
+        echo '#!/bin/sh' > $tgtfile
+        echo '[ -r /etc/lsb-release ] && . /etc/lsb-release' >> $tgtfile
+        echo 'printf "Welcome to %s (%s %s %s)\n" "$DISTRIB_DESCRIPTION" "$(uname -o)" "$(uname -r)" "$(uname -m)"' >> $tgtfile
+
+        tgtfile=$RFSDIR/etc/update-motd.d/10-help-text
+        echo '#!/bin/sh' > $tgtfile
+        echo 'printf "\n"' >> $tgtfile
+        echo 'printf " * Support:        https://www.phytium.com.cn\n"' >> $tgtfile
+
+        tgtfile=$RFSDIR/usr/lib/os-release
+        echo NAME=\"$distroname\" > $tgtfile
+        echo VERSION=${DISTROTYPE}-$distroversion >> $tgtfile
+        echo ID=ubuntu >> $tgtfile
+        echo VERSION_ID=$distroversion >> $tgtfile
+        echo PRETTY_NAME=\"Ubuntu Built with Buildroot, based on Ubuntu $distroversion LTS\" >> $tgtfile
+        echo VERSION_CODENAME=$distro >> $tgtfile
+
+        rm -f $RFSDIR/etc/default/motd-news
+        rm -f $RFSDIR/etc/update-motd.d/50-motd-news
+    fi
+}
+
+plat_name()
+{
+	echo "phytium"
+}
+
+arch_type()
+{
+	if grep -Eq "^BR2_aarch64=y$" ${BR2_CONFIG}; then
+		echo "arm64"
+	elif grep -Eq "^BR2_arm=y$" ${BR2_CONFIG}; then
+		echo "armhf"
+	fi
+}
+
+full_rtf()
+{
+	if grep -Eq "^BR2_PACKAGE_ROOTFS_DESKTOP=y$" ${BR2_CONFIG}; then
+		echo "desktop"
+	else
+		echo "base"
+	fi
+}
+
+ubuntu_distro()
+{
+	if grep -Eq "^BR2_ROOTFS_SKELETON_UBUNTU_FOCAL=y$" ${BR2_CONFIG}; then
+		echo "focal"
+	else
+		echo "jammy"
+	fi
+}
+
+main()
+{
+	# $1 - the current rootfs directory, skeleton-custom or target
+	rm -rf $1/*
+
+	# run first stage do_distrorfs_first_stage arm64 ${1} ubuntu-additional_packages_list focal ubuntu
+	do_distrorfs_first_stage $(arch_type) ${1} ubuntu-additional_packages_list $(ubuntu_distro) ubuntu $(plat_name) $(full_rtf)
+
+	# change the hostname to "platforms-Ubuntu"
+	echo $(plat_name)-Ubuntu > ${1}/etc/hostname
+
+	sed -i "s/float(n\[0\])/float(n[0].split()[0])/" ${1}/usr/share/pyshared/lsb_release.py
+
+	exit $?
+}
+
+main $@
diff --git a/board/phytium/common/ubuntu-additional_packages_list b/board/phytium/common/ubuntu-additional_packages_list
new file mode 100644
index 00000000..af2befde
--- /dev/null
+++ b/board/phytium/common/ubuntu-additional_packages_list
@@ -0,0 +1,11 @@
+# additional packages list for SDK main userland gathered from main repo
+additional_full_packages_list=" "
+
+additional_desktop_packages_list="network-manager-gnome"
+
+# for Lite userland gathered from main repo
+additional_base_packages_list="net-tools iputils-ping gcc g++ vim make autoconf automake libtool pkg-config bison bc flex libssl-dev openssh-server python-is-python3 \
+libgstreamer1.0-0 gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly gstreamer1.0-libav gstreamer1.0-tools \
+gstreamer1.0-x gstreamer1.0-alsa gstreamer1.0-gl gstreamer1.0-gtk3 gstreamer1.0-pulseaudio \
+dkms initramfs-tools debhelper libgles-dev libexpat1-dev libglvnd-dev ffmpeg \
+network-manager wpasupplicant wireless-tools parted locales"
diff --git a/board/phytium/common/ubuntu-package-installer b/board/phytium/common/ubuntu-package-installer
new file mode 100755
index 00000000..9d33f56e
--- /dev/null
+++ b/board/phytium/common/ubuntu-package-installer
@@ -0,0 +1,136 @@
+#!/bin/bash
+
+DISTROTYPE=$3
+DISTROSCALE=$5
+tarch=$1
+
+do_distrorfs_second_stage() {
+    [ -f /etc/buildinfo -a ! -f /proc/uptime ] && return
+    packages_list=/usr/aptpkg/$4
+    . $packages_list
+
+    echo "1." $1
+    echo "2." $2
+    echo "3." $3
+    echo "4." $4
+    echo "5." $5
+    echo "6." $6
+    if [ ! -d /home/user ]; then
+    	useradd -m -d /home/user -s /bin/bash user
+    	gpasswd -a user sudo
+    	echo -e 'root\nroot\n' | passwd root
+    	echo -e 'user\nuser\n' | passwd user
+    	usermod -aG sudo user
+	chown -R user:user /home/user
+    fi
+    if [ -d /etc/shadow ]; then
+	cd /etc
+	chmod u=rw,g=r,o=r shadow
+    fi
+    # set default hostname
+    echo localhost > /etc/hostname
+
+    test -f /proc/uptime || mount -t proc proc /proc
+
+    # set apt sources list to install additional packages
+    asl=/etc/apt/sources.list
+    rm -f $asl
+    cat <<-EOF > $asl
+	deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ $2 main restricted universe multiverse
+	deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ $2-updates main restricted universe multiverse
+	deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ $2-backports main restricted universe multiverse
+	deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ $2-security main restricted universe multiverse
+	EOF
+    chmod +777 /tmp
+    DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C \
+    apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" update || exit 1
+
+    DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C \
+    apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" upgrade || exit 1
+    echo upgraded
+
+    export LC_ALL=C LANGUAGE=C LANG=C
+
+    echo installing base packages: $pkglist
+    for pkg in $additional_base_packages_list; do
+	echo Installing $pkg ...
+	DEBIAN_FRONTEND=noninteractive apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" install $pkg || exit 1
+    done
+
+    dpkg -l | grep linux-headers | cut -d ' ' -f3 | xargs dpkg --purge
+
+    test -f /dev/pts/ptmx || mount -t devpts devpts /dev/pts
+
+    echo installed additional packages.
+    if [ $6 = desktop ]; then
+	for pkg in xfce4 ukui-greeter; do
+                DEBIAN_FRONTEND=noninteractive apt -y install $pkg || true
+	done
+	if [ $2 = jammy ]; then
+		sed -i 's/debian-x-terminal-emulator/gnome-terminal/g' /etc/xdg/xfce4/helpers.rc || true
+		DEBIAN_FRONTEND=noninteractive apt -y install software-properties-common || true
+		DEBIAN_FRONTEND=noninteractive add-apt-repository -y ppa:mozillateam/ppa || true
+		sed -i 's/ppa.launchpadcontent.net/launchpad.proxy.ustclug.org/g' /etc/apt/sources.list.d/mozillateam-*.list && \
+		DEBIAN_FRONTEND=noninteractive apt -y update || true
+		cat <<-EOF > /etc/apt/preferences.d/mozillateamppa
+		Package: firefox
+		Pin: release o=LP-PPA-mozillateam
+		Pin-Priority: 501
+		EOF
+	fi
+	DEBIAN_FRONTEND=noninteractive apt -y install firefox || true
+
+	usermod -a -G video,render,audio user
+	
+	ln -sf /lib/systemd/system/lightdm.service /etc/systemd/system/display-manager.service
+	sed -i "s/gdm3/lightdm/" /etc/X11/default-display-manager
+	echo '[SeatDefaults]'  >> /etc/lightdm/lightdm.conf
+	echo 'greeter-session=ukui-greeter'  >> /etc/lightdm/lightdm.conf
+	echo 'user-session=xfce'  >> /etc/lightdm/lightdm.conf
+
+	echo installing desktop packages: $pkglist
+	for pkg in $additional_desktop_packages_list; do
+		echo Installing $pkg ...
+		DEBIAN_FRONTEND=noninteractive apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" install $pkg || exit 1
+	done
+    fi
+    # clean cached packages
+    apt-get clean
+
+
+    if [ $1 = arm64 ]; then
+	sysarch=aarch64-linux-gnu
+    elif [ $1 = armhf ]; then
+	sysarch=arm-linux-gnueabihf
+    fi
+
+
+    [ -f /usr/bin/sudo -a ! -u /usr/bin/sudo ] && chmod +s /usr/bin/sudo
+    [ -d /var/cache/man ] && chown -R man:root /var/cache/man
+    [ -d /var/lib/sddm ] && chown -R sddm:sddm /var/lib/sddm
+
+    # some shared libraries locate in /lib/aarch64-linux-gnu(or /lib/arm-linux-gnueabihf) and /usr/local/lib
+    echo export LD_LIBRARY_PATH=/usr/local/lib:/usr/lib/$sysarch:/lib/$sysarch >> /etc/profile
+
+    tmpusr=`ls -t /home | cut -d' ' -f1 | head -1`
+    [ -d /home/$tmpusr -a "$tmpusr" != "user" ] && rm -rf /home/$tmpusr
+
+    test -c /dev/pts/ptmx && umount /dev/pts
+    test -f /proc/uptime && umount /proc
+
+    echo APT Packages List: > /etc/packages.list
+    echo -e "Package\t Version\t Download-Size\t APT-Sources" >> /etc/packages.list
+    apt list --installed | cut  -d/ -f1 | xargs apt show | \
+	grep -E '^Package:|^APT-Sources:|^Version:|^Download-Size:'  > packagelist
+    lnum=`wc -l packagelist |cut -d' ' -f1`
+    for((i=1; i<$lnum;)); do
+	t=$[ $i + 3 ]
+	sed -n "${i},${t}p"  packagelist | grep -E 'Package:|APT-Sources:|Version:|Download-Size:' | \
+	tr "\n" " "  | cut -d' ' -f2,4,6,7,9,10 >> /etc/packages.list
+	i=$[ $i + 4 ]
+    done
+    rm -f packagelist
+}
+
+do_distrorfs_second_stage $1 $2 $3 $4 $5 $6
+# end second stage installing