NixOS on ARM/Raspberry Pi 4
Raspberry Pi 4 Family | |
---|---|
(Image not available) | |
Manufacturer | Raspberry Pi Foundation |
Architecture | AArch64 |
Bootloader | Custom or U-Boot |
Boot order | Configurable; SD, USB, Netboot |
Maintainer | |
Raspberry Pi 4B | |
SoC | BCM2711 |
The Raspberry Pi family of devices is a series of single-board computers made by the Raspberry Pi Foundation. They are all based on Broadcom System-on-a-chip (SOCs).
Status
The Raspberry Pi 4 Family is only supported as AArch64. Use as armv7 is community supported.
Board-specific installation notes
First follow the generic installation steps to get the installer image and install using the installation and configuration steps.
The Raspberry Pi 4B should work with either the generic SD image or the new kernel variant, starting with 21.05 (or unstable). As long as a kernel 5.10 or newer is in use.
Please note: to uncompress the .zstd, one may use the unzstd
command (equivalent to zstd -d
) on supported machines. The zstd commands can be accessed from the zstd
package.
Sample instructions for installing NixOS on a Raspberry Pi are available at nix.dev.
Configuration
Using nixos-generate-config
will not generate the required minimal configuration.
Remember to add the nixos-unstable channel.
/etc/nixos/configuration.nix
{ config, pkgs, lib, ... }:
{
# This configuration worked on 09-03-2021 nixos-unstable @ commit 102eb68ceec
# The image used https://hydra.nixos.org/build/134720986
boot = {
kernelPackages = pkgs.linuxPackages_rpi4;
tmpOnTmpfs = true;
initrd.availableKernelModules = [ "usbhid" "usb_storage" ];
# ttyAMA0 is the serial console broken out to the GPIO
kernelParams = [
"8250.nr_uarts=1"
"console=ttyAMA0,115200"
"console=tty1"
# Some gui programs need this
"cma=128M"
];
};
boot.loader.raspberryPi = {
enable = true;
version = 4;
};
boot.loader.grub.enable = false;
boot.loader.generic-extlinux-compatible.enable = true;
# Required for the Wireless firmware
hardware.enableRedistributableFirmware = true;
networking = {
hostName = "nixos-raspi-4"; # Define your hostname.
networkmanager = {
enable = true;
};
};
environment.systemPackages = with pkgs; [
neovim
];
users = {
defaultUserShell = pkgs.zsh;
mutableUsers = false;
users.root = {
password = "apassword";
};
users.anormaluser = {
isNormalUser = true;
password = "apassword";
extraGroups = [ "wheel" ]; # Enable ‘sudo’ for the user.
};
};
environment.variables = {
EDITOR = "nvim";
};
programs.zsh = {
enable = true;
syntaxHighlighting.enable = true;
interactiveShellInit = ''
source ${pkgs.grml-zsh-config}/etc/zsh/zshrc
'';
promptInit = ""; # otherwise it'll override the grml prompt
};
nix = {
autoOptimiseStore = true;
gc = {
automatic = true;
dates = "weekly";
options = "--delete-older-than 30d";
};
# Free up to 1GiB whenever there is less than 100MiB left.
extraOptions = ''
min-free = ${toString (100 * 1024 * 1024)}
max-free = ${toString (1024 * 1024 * 1024)}
'';
};
# Assuming this is installed on top of the disk image.
fileSystems = {
"/" = {
device = "/dev/disk/by-label/NIXOS_SD";
fsType = "ext4";
options = [ "noatime" ];
};
};
nixpkgs.config = {
allowUnfree = true;
};
powerManagement.cpuFreqGovernor = "ondemand";
system.stateVersion = "20.09";
#swapDevices = [ { device = "/swapfile"; size = 3072; } ];
}
USB boot
For USB booting to work properly, a firmware update might be needed:
$ nix-shell -p raspberrypi-eeprom $ rpi-eeprom-update -d -a
Now reboot the device so it can update the firmware from boot partition.
When running from USB device without SD card present, kernel spams log about missing SD card, workaround for this is to set:
/etc/nixos/configuration.nix
{
boot.loader.raspberryPi.firmwareConfig = "dtparam=sd_poll_once=on";
}
GPU support
The following configuration samples are built on the assumption that they are added to an already working configuration. They are not complete configurations.
Without GPU
/etc/nixos/configuration.nix
{
services.xserver = {
enable = true;
displayManager.lightdm.enable = true;
desktopManager.gnome3.enable = true;
videoDrivers = [ "fbdev" ];
};
}
With GPU
In nixos-hardware#261 a new option has been added to use the fkms-3d
overlay. This will only work with the vendor kernel.
/etc/nixos/configuration.nix
{ pkgs, ... }:
{
imports = [
.../nixos-hardware/raspberry-pi/4
];
hardware.raspberry-pi."4".fkms-3d.enable = true;
services.xserver = {
enable = true;
displayManager.lightdm.enable = true;
desktopManager.gnome3.enable = true;
};
}
Tools
The raspberry tools are available in the libraspberrypi
package and include commands like vcgencmd
to measure temperature and CPU frequency.
Audio
In addition to the usual config, you will need to enable audio support explicitly in the firmwareConfig.
/etc/nixos/configuration.nix
sound.enable = true;
hardware.pulseaudio.enable = true;
boot.loader.raspberryPi.firmwareConfig = ''
dtparam=audio=on
'';
Gpio
Add gpio group and change permission for all users in new gpio group. Now all users in gpio group have access to /dev/gpiomem and to gpio pins via sysfs.
/etc/nixos/configuration.nix
# add gpio group
users.groups.gpio = {};
# udev rule for gpio
services.udev.extraRules = ''
SUBSYSTEM=="bcm2835-gpiomem", KERNEL=="gpiomem", GROUP="gpio",MODE="0660"
SUBSYSTEM=="gpio", KERNEL=="gpiochip*", ACTION=="add", RUN+="${pkgs.bash}/bin/bash -c 'chown root:gpio /sys/class/gpio/export /sys/class/gpio/unexport ; chmod 220 /sys/class/gpio/export /sys/class/gpio/unexport'"
SUBSYSTEM=="gpio", KERNEL=="gpio*", ACTION=="add",RUN+="${pkgs.bash}/bin/bash -c 'chown root:gpio /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value ; chmod 660 /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value'"
'';
# add user with gpio group
users = {
mutableUsers = false;
users.mygpiouser = {
isNormalUser = true;
password = "mygpiouserpasswd";
extraGroups = [ "wheel" "gpio" ];
};
};
Notes about the boot process
Unless using an extremely early WIP image, the Raspberry Pi 4B boots using the U-Boot platform firmware.
Updating U-Boot
These steps can be followed to update the platform firmware.
Troubleshooting
Power issues
The Raspberry Pi 4B is as power-hungry, if not more, as its predecessors. It is important to have a sufficient enough power supply or weirdness may happen. Weirdness may include:
- Lightning bolt icon on HDMI output "breaking" the display.
- Screen switching back to u-boot text
- Fixable temporarily when power is sufficient by switching VT (alt+F2 / alt+F1)
- Random hangs
Note that the Type-C USB receptacle for the Raspberry Pi 4B does not implement Power Delivery (USB PD). This means that it is limited to whatever the power supply will provide when not negotiating power, which is most likely 5V at some undetermined power level.