Turn a chroot environment into a bootable image.

$ debootstrap --variant=minbase bionic bionic_tree
$ debootstick --config-root-password-none bionic_tree img.dd
$ dd if=img.dd of=/dev/<your_device> bs=10M

Your USB device now embeds a live Ubuntu system and can be booted on any UEFI or BIOS computer.

A more interesting example:

$ docker run -it --name mycontainer --entrypoint /bin/bash eduble/rpi-stretch-mini
> [... customize ...]
> exit
$ mkdir mycontainer_fs; cd mycontainer_fs
$ docker export mycontainer | tar xf - ; docker rm mycontainer
$ cd ..
$ debootstick --config-root-password-none mycontainer_fs rpi.dd
$ dd if=rpi.dd of=/dev/mmcblk0 bs=10M

Your Raspberry Pi now boots your customized OS!

The embedded system is:

• ready to be used (no installation step)
• viable in the long-term, fully upgradable (including the kernel and the bootloader)
• compatible with BIOS and UEFI systems (PC) or Raspberry Pi boards

On the wiki at https://github.com/drakkar-lig/debootstick/wiki, you will find:

• A more complete workflow for designing and testing an image
• How to install debootstick
• How to combine debootstrap or docker with debootstick
• How to test images with kvm
• Design notes, FAQ