Install Debian with Debootstrap + Grub EFI

build.sh

#!/bin/bash
# SPDX-License-Identifier: MIT

set -e # Exit on error

DEVICE=$1
[ -z "${DEVICE}" ] && echo "Usage $0 /dev/sdX" && exit 1

udevadm info -n ${DEVICE} -q property
echo "Selected device is ${DEVICE}"
read -p "[Press enter to continue or CTRL+C to stop]"

echo "Umount ${DEVICE}"
umount ${DEVICE}* || true

echo "Set partition table to GPT (UEFI)"
parted ${DEVICE} --script mktable gpt

echo "Create EFI partition"
parted ${DEVICE} --script mkpart EFI fat16 1MiB 10MiB
parted ${DEVICE} --script set 1 msftdata on

echo "Create OS partition"
parted ${DEVICE} --script mkpart LINUX btrfs 10MiB 100%

echo "Format partitions"
mkfs.vfat -n EFI ${DEVICE}1
mkfs.btrfs -f -L LINUX ${DEVICE}2

echo "Mount OS partition"
ROOTFS="/tmp/installing-rootfs"
mkdir -p ${ROOTFS}
mount ${DEVICE}2 ${ROOTFS}

echo "Debootstrap system"
debootstrap --variant=minbase --arch amd64 buster ${ROOTFS} http://deb.debian.org/debian/

echo "Mount EFI partition"
mkdir -p ${ROOTFS}/boot/efi
mount ${DEVICE}1 ${ROOTFS}/boot/efi

echo "Get ready for chroot"
mount --bind /dev ${ROOTFS}/dev
mount -t devpts /dev/pts ${ROOTFS}/dev/pts
mount -t proc proc ${ROOTFS}/proc
mount -t sysfs sysfs ${ROOTFS}/sys
mount -t tmpfs tmpfs ${ROOTFS}/tmp

echo "Entering chroot, installing Linux kernel and Grub"
cat << EOF | chroot ${ROOTFS}
  set -e
  export HOME=/root
  export DEBIAN_FRONTEND=noninteractive
  debconf-set-selections <<< "grub-efi-amd64 grub2/update_nvram boolean false"
  apt-get remove -y grub-efi grub-efi-amd64
  apt-get update
  apt-get install -y linux-image-amd64 linux-headers-amd64 grub-efi
  grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=debian --recheck --no-nvram --removable
  update-grub
EOF


echo "Unmounting filesystems"
umount ${ROOTFS}/dev/pts
umount ${ROOTFS}/dev
umount ${ROOTFS}/proc
umount ${ROOTFS}/sys
umount ${ROOTFS}/tmp
umount ${ROOTFS}/boot/efi
umount ${ROOTFS}

echo "Done"

LICENCE.txt

MIT LICENSE

Copyright 2018 Quentin Dufour

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

I've added a MIT license, hope it will help.

@superboum , thank you! I've published Devuan version, based on your script: https://gitlab.com/vazhnov/devuan-debootstrap-grub-efi