rpi-pxe-server | go PXE TFTP network boot server

You can change and push a new Dockerfile to your application if you want to carefully update your device to do this differently, or for quick changes there's an SSH port exposed that allows root login with the default password of 'resin'.
Set up your device, with reliable power, a network cable, and optionally wifi (if you want logging or easy access).
Sign up for free on resin.io, create an application, and provision it, optionally with your wifi credentials.
Set the following environmental variables: RESIN_SUPERVISOR_DELTA: 1 // Enables deltas for updates keeping later changes quick
Clone/fork this repo, and push it to your resin.io application's repository to deploy this setup.
Set up your specific PXE config over samba (to /tftp), SCP (to /data/tftp), or over tftp by: Uploading your PXE bootable image Adding your PXE config at pxelinux.cfg/default
You're ready to go: put the device on the same network as the target machine (directly or through a router, as long as DHCP is disabled on the router), tell that target machine to boot from the network, and enjoy.