mkdir ubuntu
cd ubuntu
wget http://sg.cdimage.ubuntu.com/ubuntu-base/daily/current/focal-base-arm64.tar.gz
tar -xzf *.tar.gz
cat /etc/resolv.conf >etc/resolv.conf
chroot .
apt update
apt install locales-all build-essential

mount -t proc proc /proc
mount -t sysfs sys /sys
mount -t devtmpfs udev /dev
mount -t devpts devpts /dev/pts