diff --git a/flake.nix b/flake.nix
index e98881e..09366c7 100644
--- a/flake.nix
+++ b/flake.nix
@@ -19,10 +19,7 @@
       defaultModules = [
         ({ ... }: {
           # Let 'nixos-version --json' know about the Git revision
-          system.configurationRevision =
-            if self ? rev
-            then self.rev
-            else throw "Refusing to build from a dirty Git tree!";
+          system.configurationRevision = self.rev or "dirty";
         })
         {
           nixpkgs.overlays = (lib.attrValues self.overlays) ++ [