diff --git a/.github/workflows/nix.yml b/.github/workflows/nix.yml
deleted file mode 100644
index 3452ff1..0000000
--- a/.github/workflows/nix.yml
+++ /dev/null
@@ -1,18 +0,0 @@
-name: "Nix"
-on:
-  push:
-    branches:
-      - master
-  pull_request:
-jobs:
-  tests:
-    runs-on: ubuntu-20.04
-    steps:
-    - uses: actions/checkout@v2
-    - uses: cachix/install-nix-action@v14
-    - uses: cachix/cachix-action@v10
-      with:
-        extraPullNames: nixpkgs-update
-        name: nix-community
-        signingKey: ${{ secrets.CACHIX_SIGNING_KEY }}
-    - run: ./ci.sh
diff --git a/default.nix b/ci.nix
similarity index 76%
rename from default.nix
rename to ci.nix
index 1acd3eb..5ac4849 100644
--- a/default.nix
+++ b/ci.nix
@@ -13,6 +13,8 @@ pkgs.nix-community-infra // rec {
   build01-system = build01.system;
   build02 = importNixOS ./build02/configuration.nix "x86_64-linux";
   build02-system = build02.system;
-  build03 = importNixOS ./build02/configuration.nix "x86_64-linux";
+  build03 = importNixOS ./build03/configuration.nix "x86_64-linux";
   build03-system = build03.system;
+  build04 = importNixOS ./build04/configuration.nix "aarch64-linux";
+  build04-system = build04.system;
 }
diff --git a/ci.sh b/ci.sh
index 220f7cc..9a8d8fa 100755
--- a/ci.sh
+++ b/ci.sh
@@ -2,4 +2,4 @@
 # Run this command to reproduce CI
 set -euo pipefail
 cd "$(dirname "$0")"
-nix-build --no-out-link
+nix-build --no-out-link ci.nix