diff --git a/.github/workflows/flake-check.yml b/.github/workflows/flake-check.yml
deleted file mode 100644
index 3194ccb..0000000
--- a/.github/workflows/flake-check.yml
+++ /dev/null
@@ -1,46 +0,0 @@
-name: "Flake checks"
-on:
-  pull_request:
-  push:
-    branches:
-      - main
-      - release-*
-jobs:
-
-  flake-checks:
-    runs-on: ubuntu-latest
-    outputs:
-      matrix: ${{ steps.set-matrix.outputs.matrix }}
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          # Nix Flakes doesn't work on shallow clones
-          fetch-depth: 0
-      - uses: cachix/install-nix-action@v18
-        with:
-          nix_path: nixpkgs=channel:nixos-unstable
-      - id: set-matrix
-        run: |
-          set -euo pipefail
-
-          matrix="$(nix flake show --json | jq '.checks."x86_64-linux" | keys' | jq -rcM '{attr: ., os: ["ubuntu-latest", "macos-latest"]}')"
-          echo "::set-output name=matrix::$matrix"
-
-  builds:
-    needs: flake-checks
-    runs-on: ${{ matrix.os }}
-    strategy:
-      matrix: ${{fromJSON(needs.flake-checks.outputs.matrix)}}
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          # Nix Flakes doesn't work on shallow clones
-          fetch-depth: 0
-      - uses: cachix/install-nix-action@v18
-        with:
-          nix_path: nixpkgs=channel:nixos-unstable
-      - run: |
-          set -euo pipefail
-
-          system=$(nix-instantiate --eval --expr builtins.currentSystem | jq -r)
-          nix build -L .#checks.$system.${{ matrix.attr }}
diff --git a/.github/workflows/test-develop-flakes.yml b/.github/workflows/tests.yml
similarity index 77%
rename from .github/workflows/test-develop-flakes.yml
rename to .github/workflows/tests.yml
index 080f0a0..6702da1 100644
--- a/.github/workflows/test-develop-flakes.yml
+++ b/.github/workflows/tests.yml
@@ -1,4 +1,4 @@
-name: "Development workflow"
+name: "Tests"
 on:
   pull_request:
   push:
@@ -17,6 +17,10 @@ jobs:
           # Nix Flakes doesn't work on shallow clones
           fetch-depth: 0
     - uses: cachix/install-nix-action@v18
+      with:
+        github_access_token: ${{ secrets.GITHUB_TOKEN }}
+        extra_nix_config: |
+          accept-flake-config = true
     - name: Build
       run: nix develop -c bash -c 'meson build && cd build && ninja'
     - name: Run tests
diff --git a/flake.nix b/flake.nix
index c934680..9259fab 100644
--- a/flake.nix
+++ b/flake.nix
@@ -5,6 +5,13 @@
   inputs.flake-parts.url = "github:hercules-ci/flake-parts";
   inputs.flake-parts.inputs.nixpkgs-lib.follows = "nixpkgs";
 
+  nixConfig.extra-substituters = [
+    "https://cache.garnix.io"
+  ];
+  nixConfig.extra-trusted-public-keys = [
+    "cache.garnix.io:CTFPyKSLcx5RMJKfLo5EEPUObbA78b0YQ2DTCJXqr9g="
+  ];
+
   outputs = inputs @ { flake-parts, ... }:
     let
       inherit (inputs.nixpkgs) lib;