diff --git a/lib/mk-gh-actions-matrix.nix b/lib/mk-gh-actions-matrix.nix
index 447b2ed2..29c70021 100644
--- a/lib/mk-gh-actions-matrix.nix
+++ b/lib/mk-gh-actions-matrix.nix
@@ -6,10 +6,9 @@
   flake = {
     lib = rec {
       nixSystemToGHPlatform = {
-        "ubuntu-latest" = "x86_64-linux";
-        "macos-latest" = "x86_64-darwin";
-        # not supported:
-        # "macos-latest-xlarge" = "aarch64-darwin";
+        "x86_64-linux" = "ubuntu-latest";
+        "x86_64-darwin" = "flyci-macos-large-latest-m1";
+        "aarch64-darwin" = "flyci-macos-large-latest-m1";
       };
 
       inherit (import ./build-status.nix {inherit lib;}) getBuildStatus;
@@ -18,8 +17,8 @@
         include = lib.pipe (builtins.attrNames nixSystemToGHPlatform) [
           (builtins.concatMap
             (
-              platform: let
-                system = nixSystemToGHPlatform.${platform};
+              system: let
+                platform = nixSystemToGHPlatform.${system};
               in
                 map (package: let
                   p = self.packages.${system}.${package};