diff --git a/nix/base-system/flake.nix b/nix/base-system/flake.nix
index 856fbe7..c51afde 100644
--- a/nix/base-system/flake.nix
+++ b/nix/base-system/flake.nix
@@ -235,7 +235,9 @@ EOF";
           };
         };
         environment.systemPackages = (with pkgs; [
-            #isabelle # TODO(jwall): See if there is a way to pin this to a working build
+            # TODO(jwall): This appears to be broken due to: https://github.com/NixOS/nixpkgs/issues/166205
+            # Should be fixed by: https://github.com/NixOS/nixpkgs/pull/282624
+            #unstablePkgs.isabelle
             terraform # TODO(jeremy): Replace with opentofu when that is an option.
             consul
             consul-template