Enable ISO ARM cross-compilation & update CI config

- Allow rune to cross compile ARM binaries
- Github workflow only compiles x86 for now

.github/workflows/build-iso.yml

@@ -1,4 +1,4 @@
-name: Build NixOS ISOs
+name: Build NixOS ISOs (x86 only)
 
 on:
   push:
@@ -16,23 +16,10 @@ jobs:
   build-iso:
     strategy:
       matrix:
-        include:
-          # x86 ISOs on x86 runners
-          - iso-type: server
-            arch: x86
-            runner: ubuntu-latest
-          - iso-type: desktop
-            arch: x86
-            runner: ubuntu-latest
-          # ARM ISOs on ARM runners
-          - iso-type: server
-            arch: arm
-            runner: ubuntu-latest-arm64
-          - iso-type: desktop
-            arch: arm
-            runner: ubuntu-latest-arm64
+        iso-type: [server, desktop]
+        arch: [x86]
 
-    runs-on: ${{ matrix.runner }}
+    runs-on: ubuntu-latest
 
     steps:
       - name: Checkout repository
@@ -47,12 +34,12 @@ jobs:
       - name: Build ISO (with retry)
         uses: nick-fields/retry@v3
         with:
-          timeout_minutes: 60
+          timeout_minutes: 45
           max_attempts: 3
           retry_wait_seconds: 30
           command: |
             cd iso
-            nix build .#${{ matrix.iso-type }}-iso-${{ matrix.arch }} \
+            nix build .#${{ matrix.iso-type }}-iso-x86 \
               --print-build-logs \
               --accept-flake-config
 
@@ -60,7 +47,7 @@ jobs:
         id: iso-info
         run: |
           cd iso
-          ISO_PATH=$(nix build .#${{ matrix.iso-type }}-iso-${{ matrix.arch }} --print-out-paths --no-link)
+          ISO_PATH=$(nix build .#${{ matrix.iso-type }}-iso-x86 --print-out-paths --no-link)
           ISO_FILE=$(find $ISO_PATH -name "*.iso" -o -name "*.iso.zst" | head -1)
           ISO_NAME=$(basename "$ISO_FILE")
           echo "iso-path=$ISO_FILE" >> $GITHUB_OUTPUT
@@ -96,10 +83,9 @@ jobs:
             This release contains automatically built NixOS ISOs based on my configuration.
 
             ### Available ISOs:
-            - **Server ISOs**: Minimal server environment with SSH access
-            - **Desktop ISOs**: GNOME desktop environment for installation
-            - **x86**: Intel/AMD 64-bit systems
-            - **ARM**: ARM64 systems
+            - **Server ISO**: Minimal server environment with SSH access
+            - **Desktop ISO**: GNOME desktop environment for installation
+            - **Architecture**: x86_64 (Intel/AMD systems)
 
             ### Usage:
             1. Download the appropriate ISO for your system
@@ -107,6 +93,8 @@ jobs:
             3. Default credentials: user `nixos`, password `nixos`
             4. SSH is enabled for remote installation
 
+            Note: ARM ISOs are not provided in this build. Users requiring ARM versions should build locally.
+
             Built automatically from commit: ${{ github.sha }}
           draft: false
-          prerelease: false
+          prerelease: false

iso/default.nix

@@ -7,15 +7,17 @@
   system,
   ...
 }:
+let
+  isCross = pkgs.stdenv.buildPlatform.system != pkgs.stdenv.hostPlatform.system;
+in
 {
-  ## ISO ##
   isoImage = {
     isoName = lib.mkForce "nixos-${config.hostSpec.hostName}-${config.system.nixos.label}-${pkgs.stdenv.hostPlatform.system}.iso";
     makeEfiBootable = true;
     makeUsbBootable = true;
     compressImage = false;
     squashfsCompression = lib.mkIf isARM "gzip";
-    includeSystemBuildDependencies = lib.mkIf isARM false;
+    includeSystemBuildDependencies = lib.mkIf (isARM || isCross) false;
   };
 
   ## SSH  & NETWORK ##
@@ -56,7 +58,6 @@
   system.stateVersion = "25.05";
   nixpkgs.hostPlatform = system;
   users.mutableUsers = lib.mkForce true; # Allow password changes
-  boot.kernelPackages = pkgs.linuxPackages_latest;
 
   nixpkgs.config = {
     allowUnsupportedSystem = true;

iso/flake.nix

@@ -87,7 +87,7 @@
           }) configs
         );
 
-      # Generate packages per system - each system only exposes its own packages
+      # Generate packages per system - all available on x86_64 via cross-compilation
       mkPackages =
         system:
         let
@@ -103,13 +103,11 @@
     {
       nixosConfigurations = mkConfigurations;
 
-      # Each system only exposes packages it can build
       packages = {
-        "${X86}" = mkPackages X86;
+        "${X86}" = (mkPackages X86) // (mkPackages ARM);
         "${ARM}" = mkPackages ARM;
       };
 
-      # For convenience - all systems get all configs
       inherit (dot-nix.outputs) overlays;
     };
 }