#https://wiki.debian.org/EmDebian/CrossDebootstrap#QEMU.2Fdebootstrap_approach
sudo apt-get install binfmt-support qemu qemu-user-static debootstrap

arch="mipsel"
version="bookworm"
dir="debian_${version}_${arch}"

#create empty image and mount it
img="debian_${version}_${arch}.img"
dd bs=512 count=5400000 if=/dev/zero of=$img #creates a empty IMG file that is about 2GB
 
mkfs.ext4 -F "$img"
 
mkdir $dir

sudo modprobe loop
sudo mount -o loop "$img" "$dir"
 
sudo debootstrap --foreign --arch "$arch" "$version" "$dir" http://ftp.debian.org/debian/
 
sudo cp -v /usr/bin/qemu-${arch}-static $dir/usr/bin
 
sudo DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true \
 LC_ALL=C LANGUAGE=C LANG=C chroot $dir /debootstrap/debootstrap --second-stage
 
sudo DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true \
 LC_ALL=C LANGUAGE=C LANG=C chroot $dir dpkg --configure -a
 
echo "Welcome to your ${arch} chroot\!"
 
sudo chroot $dir bash