diff --git a/.github/workflows/build-system.yml b/.github/workflows/build-system.yml
new file mode 100644
index 0000000..73945ab
--- /dev/null
+++ b/.github/workflows/build-system.yml
@@ -0,0 +1,38 @@
+name: Build system configurations
+
+on:
+  pull_request:
+
+jobs:
+  build-x86_64-demeter:
+    runs-on: ubuntu-22.04
+    permissions:
+      contents: read
+      id-token: write
+    steps:
+      - name: Free Disk Space (Ubuntu)
+        uses: jlumbroso/free-disk-space@v1.3.1
+      - uses: actions/checkout@v4
+      - name: Check Nix flake Nixpkgs inputs
+        uses: DeterminateSystems/flake-checker-action@main
+      - uses: DeterminateSystems/nix-installer-action@main
+      - name: Build select system configurations.
+        run: |
+          # nix flake check --all-systems
+          nix build .#nixosConfigurations.demeter.config.system.build.toplevel
+  build-aarch64-callisto:
+    runs-on: ubuntu-24.04-arm
+    permissions:
+      contents: read
+      id-token: write
+    steps:
+      - name: Free Disk Space (Ubuntu)
+        uses: jlumbroso/free-disk-space@v1.3.1
+      - uses: actions/checkout@v4
+      - name: Check Nix flake Nixpkgs inputs
+        uses: DeterminateSystems/flake-checker-action@main
+      - uses: DeterminateSystems/nix-installer-action@main
+      - name: Build select system configurations.
+        run: |
+          # nix flake check --all-systems
+          nix build .#nixosConfigurations.callisto.config.system.build.toplevel
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
deleted file mode 100644
index 6075acd..0000000
--- a/.github/workflows/main.yml
+++ /dev/null
@@ -1,22 +0,0 @@
-name: Check flake
-
-on:
-  pull_request:
-
-jobs:
-  check:
-    runs-on: ubuntu-22.04
-    permissions:
-      contents: read
-      id-token: write
-    steps:
-      - name: Free Disk Space (Ubuntu)
-        uses: jlumbroso/free-disk-space@v1.3.1
-      - uses: actions/checkout@v4
-      - name: Check Nix flake Nixpkgs inputs
-        uses: DeterminateSystems/flake-checker-action@main
-      - uses: DeterminateSystems/nix-installer-action@main
-      - name: Build select system configurations.
-        run: |
-          # nix flake check --all-systems
-          nix build .#nixosConfigurations.demeter.config.system.build.toplevel