From c517187aa9940ca3584b0de2e4147e6d3ec185e6 Mon Sep 17 00:00:00 2001 From: Adithya Nair Date: Tue, 2 Jul 2024 01:30:41 +0530 Subject: [PATCH] add page for nixos on raspberry pi 4 --- default.nix | 2 +- src/SUMMARY.md | 1 + src/nix/nix-on-pi.md | 80 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 82 insertions(+), 1 deletion(-) create mode 100644 src/nix/nix-on-pi.md diff --git a/default.nix b/default.nix index a4edeff..c136896 100644 --- a/default.nix +++ b/default.nix @@ -5,7 +5,7 @@ }: stdenvNoCC.mkDerivation { pname = "wiki"; - version = "2023-12-04"; + version = "2024-07-02"; src = ./.; buildInputs = [ mdbook mdbook-alerts ]; buildPhase = '' diff --git a/src/SUMMARY.md b/src/SUMMARY.md index 7e26e2e..00a2f1f 100644 --- a/src/SUMMARY.md +++ b/src/SUMMARY.md @@ -3,6 +3,7 @@ [What's this?](./about.md) # Nix/NixOS + - [NixOS on Raspberry Pi](./nix/nix-on-pi.md) - [Firefox + Nix](./nix/firefox.md) - [Adhoc development environments with Nix](./nix/nix-devshells.md) diff --git a/src/nix/nix-on-pi.md b/src/nix/nix-on-pi.md new file mode 100644 index 0000000..298c3a2 --- /dev/null +++ b/src/nix/nix-on-pi.md @@ -0,0 +1,80 @@ +# NixOS on Raspberry Pi 4 over USB + +> **TL;DR;** The officially supported SD image[↗](https://wiki.nixos.org/wiki/NixOS_on_ARM/Raspberry_Pi_4) available in Hydra only works when booting off of SD cards, due to some bug in U-Boot. Here's a workaround to get the Pi to boot NixOS from a USB drive or an SSD. + +### Requirements +- A Raspberry Pi 4 (duh!) +- An SD card (it will be our installer) +- A USB Drive (NixOS will be installed to it) + +### Preparing the Pi to boot from USB +Write the `misc utility images -> Bootloader (Pi 4 family) -> USB Boot` image onto an SD card using Raspberry Pi Imager (`pkgs.rpi-imager`) and boot the Pi with it. Once booted, wait for 10-15 seconds and turn off the Pi. This will update the Pi's firmware to prefer booting from USB. + +### Preparing the installer SD card (installer) +- Download a recent version of the aarch64 SD card image from [Hydra↗](https://hydra.nixos.org/job/nixos/trunk-combined/nixos.sd_image.aarch64-linux) +- The image will be compressed with ZSTD, so it needs to be decompressed before being written to the SD card + ```sh + zstd --decompress nixos-sd-image-24.11preblah.blahblah-aarch64-linux.img.zst + ``` +- Write the decompressed image to the SD card (we'll call it /dev/mmcblkN from now on) + ```sh + dd if=nixos-sd-image-24.11preblah.blahblah-aarch64-linux.img of=/dev/mmcblkN + ``` + +### Preparing the USB drive +#### Disk Layout +> [!NOTE] +> We're make it work just like a normal UEFI machine so the partitions will resemble that +- Partitioning the USB device (we'll call it /dev/sdN) + - An EFI partition (FAT32) of reasonable size (will be mounted on /boot and the kernel/initrd will go in there) + - A partition for / (ext4, btrfs or whatever's your choice) + I'm going with a 1GiB EFI partition and the remaining space as a single btrfs partition +- Format the partitions + ```sh + mkfs.vfat -F32 -n NIXOS_BOOT /dev/sdN1 + mkfs.btrfs -L NIXOS_ROOT /dev/sdN2 + ``` +#### Files +- Download the latest release of the Raspberry Pi 4 UEFI firmware [↗](https://github.com/pftf/RPi4/releases) +- Extract the contents onto the EFI partition on the USB disk + ```sh + mkdir /tmp/efi + mount /dev/sdN1 /tmp/efi + unzip RPi4_UEFI_Firmware_v1.37.zip -d /tmp/efi/ + umount /tmp/efi + ``` +#### Optional: Download the Raspberry Pi device tree overlays +> [!NOTE] +> This is only required if you need a working GPIO, to use any HATs etc. +> I need it because I power the Pi using the PoE+ HAT and the fans on the HAT doesn't work without this. +- Download a recent version of the Raspberry Pi OS[↗](https://www.raspberrypi.com/software/operating-systems/). The 64-bit Lite version should be enough. +- Extract the overlays + ```sh + losetup /dev/loop0 2024-03-15-raspios-bookworm-arm64-lite.img + partx -u /dev/loop0 + mkdir /tmp/firmware + mount /dev/loop0p1 /tmp/firmware + mkdir /tmp/efi + mount /dev/sdN1 /tmp/efi + mkdir /tmp/efi/overlays + cp /tmp/firmware/overlays/* /tmp/efi/overlays/ + umount /tmp/efi + ``` + +### Installing +Use the installed SD card prepared above to boot the Pi. (Don't plug in the USB drive yet, otherwise the Pi will try to boot from it). +Once it's successfully booted and shows the TTY, plug in the USB drive. At this point the USB drive can be mounted to `/mnt` or anywhere and NixOS can be installed to it with the `nixos-generate-config` and `nixos-install` scripts. + +If any HATs are to be used or if the GPIO is needed, make sure to change `boot.kernelPackages` to `pkgs.linuxPackages_rpi4` in the configuration.nix before doing nixos-install. + +### Post Install +Once the installation is done, power off the Pi and remove the SD card. Now turning it on with the USB drive plugged in will show a screen with a big Raspberry Pi logo. Press Esc to go to the UEFI Firmware settings. + +Two things need to be changed here. +1. There's a 3GB limit on the RAM due to a hardware bug in the Broadcom SoC. A Kernel version of 5.8 or later has a workaround for this so we can turn off the limit. +Go to `Device Manager` → `Raspberry Pi Configuration` → `Advanced Settings` in the UEFI settings and disable the 3GB limit. +2. **(Optional: only required if HATs/GPIO are used)** In the same `Advanced Settings` page, change the second item from `ACPI` to `ACPI + Device Tree` + +Hit F10 to save and use Esc to go back to the main page. Use the `Continue` option to resume booting. It will ask to reset, press Y + +If everything went well, it should now boot into Freshly installed NixOS, booted from a USB device on the Pi 4 :)