Update: I suggest to use this script instead if you care about (a bit) more free disk space and/or want to change the box’s boot splash image.

From GitHub, slightly modified.

The original source seems to be a post at right.com.cn but I was not able to download that as the forum’s registration requires an invitation.

The use of environment variable mac is removed, it does not seem to hurt.

DTB is also not used.

#!/bin/sh

echo "Start copy system for DATA partition."

mkdir -p /ddbr
chmod 777 /ddbr

VER=`uname -r`

IMAGE_KERNEL="/boot/zImage"
IMAGE_INITRD="/boot/initrd.img-$VER"
PART_ROOT="/dev/data"
DIR_INSTALL="/ddbr/install"
#IMAGE_DTB="/boot/dtb/gxl_p230_2g.dtb"


if [ ! -f $IMAGE_KERNEL ] ; then
    echo "Not KERNEL.  STOP install !!!"
    return
fi

if [ ! -f $IMAGE_INITRD ] ; then
    echo "Not INITRD.  STOP install !!!"
    return
fi


echo "Formatting DATA partition..."
umount -f $PART_ROOT
mke2fs -F -q -t ext4 -m 0 $PART_ROOT
/sbin/resize2fs -s $PART_ROOT
/sbin/tune2fs -O ^metadata_csum $PART_ROOT
e2fsck -n $PART_ROOT
echo "done."

echo "Copying ROOTFS."

if [ -d $DIR_INSTALL ] ; then
    rm -rf $DIR_INSTALL
fi

mkdir -p $DIR_INSTALL
mount -o rw $PART_ROOT $DIR_INSTALL

cd /
echo "Copy BIN"
tar -cf - bin | (cd $DIR_INSTALL; tar -xpf -)
echo "Copy BOOT"
#mkdir -p $DIR_INSTALL/boot
tar -cf - boot | (cd $DIR_INSTALL; tar -xpf -)
echo "Create DEV"
mkdir -p $DIR_INSTALL/dev
#tar -cf - dev | (cd $DIR_INSTALL; tar -xpf -)
echo "Copy ETC"
tar -cf - etc | (cd $DIR_INSTALL; tar -xpf -)
echo "Copy HOME"
tar -cf - home | (cd $DIR_INSTALL; tar -xpf -)
echo "Copy LIB"
tar -cf - lib | (cd $DIR_INSTALL; tar -xpf -)
echo "Create MEDIA"
mkdir -p $DIR_INSTALL/media
#tar -cf - media | (cd $DIR_INSTALL; tar -xpf -)
echo "Create MNT"
mkdir -p $DIR_INSTALL/mnt
#tar -cf - mnt | (cd $DIR_INSTALL; tar -xpf -)
echo "Copy OPT"
tar -cf - opt | (cd $DIR_INSTALL; tar -xpf -)
echo "Create PROC"
mkdir -p $DIR_INSTALL/proc
echo "Copy ROOT"
tar -cf - root | (cd $DIR_INSTALL; tar -xpf -)
echo "Create RUN"
mkdir -p $DIR_INSTALL/run
echo "Copy SBIN"
tar -cf - sbin | (cd $DIR_INSTALL; tar -xpf -)
echo "Copy SELINUX"
tar -cf - selinux | (cd $DIR_INSTALL; tar -xpf -)
echo "Copy SRV"
tar -cf - srv | (cd $DIR_INSTALL; tar -xpf -)
echo "Create SYS"
mkdir -p $DIR_INSTALL/sys
echo "Create TMP"
mkdir -p $DIR_INSTALL/tmp
echo "Copy USR"
tar -cf - usr | (cd $DIR_INSTALL; tar -xpf -)
echo "Copy VAR"
tar -cf - var | (cd $DIR_INSTALL; tar -xpf -)

echo "Copy fstab"

rm $DIR_INSTALL/etc/fstab
cp -a /root/fstab $DIR_INSTALL/etc
#cp -a /boot/hdmi.sh $DIR_INSTALL/boot

#add by achaoge 2018-06-22
#export $(/usr/sbin/fw_printenv mac)
echo "Modify files for N1 emmc boot"
/bin/sed -e "/usb [23]/d" -e 's/fatload mmc 0 \([^ ]*\) \([^;]*\)/ext4load mmc 1:c \1 \/boot\/\2/g' -i $DIR_INSTALL/boot/s905_autoscript.cmd
/bin/sed -e 's/LABEL=ROOTFS/\/dev\/data/' -i $DIR_INSTALL/boot/uEnv.ini
/usr/bin/mkimage -C none -A arm -T script -d $DIR_INSTALL/boot/s905_autoscript.cmd $DIR_INSTALL/boot/s905_autoscript
echo "Emmc boot fixed end"

rm $DIR_INSTALL/root/install.sh
rm $DIR_INSTALL/root/fstab
rm $DIR_INSTALL/usr/bin/ddbr
rm $DIR_INSTALL/usr/bin/ddbr_backup_nand
rm $DIR_INSTALL/usr/bin/ddbr_restore_nand

cd /
sync

umount $DIR_INSTALL

echo "*******************************************"
echo "Done copy ROOTFS"
echo "*******************************************"

# echo "Writing new kernel image..."
#
# mkdir -p $DIR_INSTALL/aboot
# cd $DIR_INSTALL/aboot
# dd if=/dev/boot of=boot.backup.img
# abootimg -i /dev/boot > aboot.txt
# abootimg -x /dev/boot
# abootimg -u /dev/boot -k $IMAGE_KERNEL
# abootimg -u /dev/boot -r $IMAGE_INITRD
#
# echo "done."
#
# if [ -f $IMAGE_DTB ] ; then
# #    abootimg -u /dev/boot -s $IMAGE_DTB
#     echo "Writing new dtb ..."
#     dd if="$IMAGE_DTB" of="/dev/dtb" bs=262144 status=none && sync
#     echo "done."
# fi

echo "Write env bootargs"
#/usr/sbin/fw_setenv initargs "root=/dev/data rootflags=data=writeback rw console=ttyS0,115200n8 console=tty0 no_console_suspend consoleblank=0 fsck.repair=yes net.ifnames=0 mac=\${mac}"

#Edit by achaoge 2018-06-22, for Phicomm N1 boot from emmc
/usr/sbin/fw_setenv start_autoscript "if usb start ; then run start_usb_autoscript; fi; if ext4load mmc 1:c 1020000 /boot/s905_autoscript; then autoscr 1020000; fi;"

echo "*******************************************"
echo "Complete copy OS to eMMC parted DATA"
echo "*******************************************"