build using nixos-install instead of docker image

README.md

@@ -0,0 +1,21 @@
+# Setup
+
+## Qemu binfmt emulation
+```
+sudo apt install binfmt-support qemu-user-static
+```
+
+### In `configuration.nix`:
+
+```nix
+{
+  boot.binfmt.emulatedSystems = [ "aarch64-linux" "armv7l-linux" ];
+}
+```
+
+### or in `/etc/nix/nix.conf`:
+
+```
+extra-platforms = aarch64-linux armv7l-linux
+extra-sandbox-paths = /usr/libexec/qemu-binfmt /usr/bin/qemu-aarch64-static /usr/bin/qemu-arm-static
+```

docker-compose.yml

@@ -1,17 +0,0 @@
-services:
-  nixos-builder:
-    container_name: nixos-builder
-    stdin_open: true
-    tty: true
-    privileged: true
-    build: ./nix-builder
-
-    volumes:
-      - nix_store:/nix
-      - ./workspace:/workspace
-      
-    environment:
-      - USER=root
-
-volumes:
-  nix_store:

nix-builder/Dockerfile

@@ -1,11 +0,0 @@
-FROM nixos/nix
-
-RUN nix-channel --add https://nixos.org/channels/nixos-unstable nixpkgs \
-    && nix-channel --update
-
-RUN nix-env -iA nixpkgs.pkgsCross nixpkgs.nixos-generators
-
-RUN mkdir /workspace
-
-WORKDIR /workspace
-CMD ["nix-shell", "-p", "nixos-generators"]

workspace/build.sh

@@ -2,7 +2,8 @@ set -e
 
 nix-build '<nixpkgs/nixos>' \
   -A config.system.build.sdImage \
-  --arg pkgs 'import <nixpkgs> { crossSystem = { system = "armv7l-linux"; }; }' \
+  --argstr system armv7l-linux \
+  --option sandbox false \
   -I nixos-config=./rpi2.nix
 
 cp result/sd-image/nixos-rpi2.img .

workspace/rpi2.nix

@@ -17,7 +17,7 @@
   # Bootloader: Use U-Boot for Raspberry Pi 2
   boot.loader.generic-extlinux-compatible.enable = true;
   hardware.deviceTree.enable = true;
-  hardware.deviceTree.name = "bcm2836-rpi-2-b.dtb"; # Correct DTB for RPi2
+  hardware.deviceTree.name = "bcm2709-rpi-2-b.dtb"; # Correct DTB for RPi2
 
   # Disable GRUB (not used on Raspberry Pi)
   boot.loader.grub.enable = false;
@@ -39,7 +39,7 @@
     })
   ];
   boot.supportedFilesystems = lib.mkForce [ "vfat" "ext4" ];
-
+  
   # Networking
   networking.hostName = "nixos-rpi2";
   networking.wireless.enable = false; # Enable this if using WiFi
@@ -58,9 +58,4 @@
   
   # Set system version (avoid warnings)
   system.stateVersion = "25.05";
-
-  # Enable cross-compilation
-  nixpkgs.crossSystem = {
-    system = "armv7l-linux";
-  };
 }