nixos-config-rpi

NixOS configuration for Raspberry Pi used in burn-in. This branch works for rpi 4 only.

Installation

Download the latest NixOS aarch64 release from 1 (Yipeng's approved images, preferred) or 2 (official, but experimental). Note that this is officially termed as 'unstable', but should be sufficient in our case. This branch can be used as a rolling release.

This image relying on the raspberry pi foundation's kernel, and the raspberry pi foundation's boot chain, rather than our preferred u-boot based images using the mainline kernel.

This specific image will not be kept for stable releases, and will be removed from Nixpkgs once a mainline-based u-boot-based generic image can boot on the raspberry pi 4.

Write the image to an SD card. In Linux, suppose we have a sdcard mmcblk0 with 2 partitions mmcblk0p1 and mmcblk0p1, then we should write to mmcblk0, not either of the partitions, with the following command:

sudo dd if=<nixos.img> of=/dev/mmcblk0

On first boot, the rootfs will be automatically resized to use all available spaces of the SD card.

After the dd command is completed, mount the /dev/mmcblk0p1 (the latter of the two partitions) to /mnt:

sudo mount /dev/mmcblk0p1 /mnt

Then clone the rpi4 NixOS configuration:

cd /mnt  # Choose the correct mount path if differs
mkdir -p etc/nixos
cd etc/nixos
git init .
git remote add origin https://github.com/umd-lhcb/nixos-config-rpi
git fetch origin
git checkout rpi4

Then umount the SD card partition.

System configuration

Plug the SD card into the rpi 4. Also attach monitor, keyboard, and internet. Since the rpis are not registered, the internet needs to be shared from another computer.

On first boot of the rpi, set the password of root with:

sudo passwd root

This password will then be overwritten by the configuration.

Then switch to root user:

su

We need to manually mount the boot partition first:

sudo mount /dev/mmcblk0p1 /boot

Now we reconfigure the system with our settings:

sudo nixos-rebuild switch

There might be some warnings and errors at this step. Ignore them. Reboot. The user lhcb with sudo permission will be created in the process. Ask Yipeng/Manuel/Zishuo for the password.

Now we add the official unstable channel:

sudo nix-channel --add https://nixos.org/channels/nixos-unstable nixos

We can update the system with:

sudo nixos-rebuild switch --upgrade

If everything works, we can remove the old system generations with:

sudo nix-collect-garbage -d