Pine: Pine Is Nix Embedded

This is an experiment in using Nix to build reproducible images for embedded systems using cross-compilation.

It uses disko and nixos-anywhere for initial deployment and target systems can later be updated via a remote nixos-rebuild Currently the only defined target is Beaglebone Black

Images

The following images are available:

• bbb-standard A generic image using pine-bbb-standard-sd
• bbb-sd-installer A minimal image for installing to the internal emmc

NixOS configurations

The flake can build the following NixOs configurations

• pine-bbb-installer A minimal installer config, not to be used directly but for building SD card image.

• pine-bbb-standard-sd A config for running of the sd-card, can be basis for a custom config.

• pine-bbb-standard-emmc A config for running of BeagleBone internal emmc meant to be written using nixos-anywhere when running sd-installer of the SD card

Important

Most of the building is done cross compiled but some steps (disko) uses QEMU this requires running armv7l-linux code using binfmt, in NixOS set binfmt.emulatedSystems = [ "armv7l-linux" ]; otherwise building won't work, for other distros check documentation

Building and installing standard image to an SD Card

1. Build and run the image generator

nix build .#images.bbb-standard
./result

2. Write to sd-card use dd or bmaptool

sudo bmaptool copy ./pine-sdcard.raw /dev/<SD-card>

Building and installing standard image to emmc

1. Build and run the installer image generator

nix build .#images.bbb-installer
./result

2. write to sd-card use dd or bmaptool

sudo bmaptool copy ./pine-installer-sdcard.raw /dev/<SD-card>

3. Boot from the SD Card

4. Install to emmc using nixos-anywhere

   • Figure out the IP of the board (ip a)
   • Login is 'pine'/'pass' and ssh is enabled

nix run .#nixos-anywhere -- --flake .#pine-bbb-standard-emmc --target-host pine@<target-ip> --build-on local

Updating an existing install using nixos-rebuild

nixos-rebuild <switch or boot> --flake .#<nixosConfiguration> --target-host pine@<target-ip> --use-remote-sudo

Note

Replace nixosConfiguration with pine-bbb-standard-emmc or pine-bbb-standard-sd if running from sd-card

TODO

• Expand partition on first boot when built for SD card
• Look into disk-by/partition-label issue