NixOS on the Raspberry Pi Zero W - I'm stumped! - Written: 06 December 2022

I have been trying for the past couple of days to run NixOS on a RaspberryPi 0W. It was much more difficult than I expected!

Tags: nixos

Recently, I have been trying to run NixOS on a RaspberryPi 0W. I have been trying for the past couple of days, but I have been unable to get it to work. I have got so far, but I am stuck.

What I have tried 

Downloading/Building the SD Card image

First, I tried compiling an SD card image using illegalprime’s nixos-on-arm repository and this command:

nix build -f . \
  -I nixpkgs=nixpkgs \
  -I machine=machines/raspberrypi-zerow \
  -I image=images/rpi0-otg-serial

Then, after a while, I tried using this downloadable sd card image which had similar problems, but included more useful tools like vim.

After writing my SD card, I connected my Raspberry Pi Zero W to a HDMI monitor and a keyboard. This worked great and soon got me to a terminal.

Setting up WiFi

Setting up WiFi was a bit of a hassle, however this is what I did to get it working:

Firstly, I created a config file for wpa_supplicant:

mkdir /etc/wpa_supplicant
nano /etc/wpa_supplicant/wpa_supplicant.conf

I put these lines inside the file and saved it:

ctrl_interface=/run/wpa_supplicant
update_config=1
ap_scan=1
country=GB
network={
  ssid="MY_SSID"
  psk="MY_PASSWORD"
  key_mgmt=WPA-PSK
}

Then, I ran these commands to clean the interface - thanks superuser.com!:

ip link set dev wlan0 down
ip addr flush dev wlan0
ip link set dev wlan0 up

And finally, I ran wpa_supplicant:

wpa_supplicant -B -i wlan0 -Dnl80211,wext -c /etc/wpa_supplicant/wpa_supplicant.conf

Updating nix-channels

Now that I had a working internet connection, I ran these commands to update my nix-channels:

nix-channel --remove nixos
nix-channel --add https://channels.nixos.org/nixos19.09 nixos # This channel is the latest one that does not complain about the nix version.
nix-channel --update # Be very patient! This might take 5-10 minutes.

The trouble

Now, I generated a new configuration file using nixos-generate-config and ran nixos-rebuild switch to install it. This is where the trouble began. I got an error complaining that the command could not connect to http://nixos-arm.dezgeg.me/. I discovered (through archive.org) that the server used to redirect to https://www.cs.helsinki.fi/u/tmtynkky/nixos-arm/, so I followed the link and the webpage is still in operation (yay!). It appears, however that for some unknown reason, the images I have been using are somewhat hardcoded to use http://nixos-arm.dezgeg.me/. I tried to force nixos-rebuild to use https://www.cs.helsinki.fi/u/tmtynkky/nixos-arm/, however I was unable to do so. I tried:

nixos-rebuild switch --option substituters https://www.cs.helsinki.fi/u/tmtynkky/nixos-arm/channel

and I also added:

nix.settings.substituters = [ "https://www.cs.helsinki.fi/u/tmtynkky/nixos-arm/channel" ];

to my configuration.nix file, but neither of these worked. I tried building from source, but after two full days of compiling, I gave up.

Want to help? 

If anyone out there has figured this out, or I am missing something obvious, raise an issue (or a pull request if you are feeling nice) on my dotfiles and I will try to fix it! I would love to get this working, as I have a few projects I would like to run on my Raspberry Pi Zero W using NixOS.

Also, I have found An armv7l cache server, but I have not been able to look into it yet.

What now? 

For now, I will be using Raspbian on my Raspberry Pi Zero W. I might try to get NixOS working again in the far future (perhaps when support is better - although that is unlikely), but for now, it is just too much hassle.