How to create Debian 10 rootfs base for iMX8/iMX6

Host Prerequisites

install required packages

sudo apt-get install binfmt-support qemu-user-static wget
sudo modprobe binfmt_misc

Building Procedures

set ARM architecture

export ARCH=arm64 # for i.MX8
export ARCH=armhf # for i.MX6

get the basic rootfs

export ROOTFS=~/rootfs_${ARCH}-deb10
sudo apt -y install debian-archive-keyring
sudo apt-key add /usr/share/keyrings/debian-archive-keyring.gpg
sudo qemu-debootstrap --arch=${ARCH} \
--keyring /usr/share/keyrings/debian-archive-keyring.gpg \
--variant=buildd \
--exclude=debfoster buster $ROOTFS http://ftp.debian.org/debian

go on in chroot

set the mount point

sudo mount -t proc proc $ROOTFS/proc
sudo mount -t sysfs sysfs $ROOTFS/sys
sudo mount --bind /dev $ROOTFS/dev
sudo mount --bind /dev/pts $ROOTFS/dev/pts

enter the chroot

HOME=/root sudo chroot $ROOTFS /bin/bash --login -i

installation

cd ~
apt-get update
apt -y install iputils-ping iproute2 lsb-release vim whois
ln -sf bash /bin/sh
ln -sf bash.1.gz /usr/share/man/man1/sh.1.gz

apt -y install sudo
apt -y install systemd systemd-sysv kmod
apt -y install network-manager
apt -y install parted

configuration

groupadd -g 1000 adv
useradd -u 1000 -d /home/adv -m -g adv -G adm,sudo,audio adv
CRYPT=$(echo adv | mkpasswd -m sha-512 -s)
sed -i "s|^adv:[^:]\+:|adv:$CRYPT:|" /etc/shadow
sed -i "s/^root:[^:]\+:/root::/" /etc/shadow
echo "unknown" > /etc/hostname
echo -e "127.0.0.1    localhost \n127.0.1.1    unknown\n" > /etc/hosts

ln -sf ../run/resolvconf/resolv.conf /etc/resolv.conf
apt-get clean
history -c

leave the chroot

logout

clear the mount point

sudo umount -lf $ROOTFS/dev/pts
sudo umount -lf $ROOTFS/dev
sudo umount $ROOTFS/sys
sudo umount $ROOTFS/proc

Basic rootfs is ready

keep the rootfs for future use

sudo tar zcvf ${ROOTFS}.tgz -C ${ROOTFS} .

Please go on to create Debian 10 SD card image if needed