1 files changed, 1 insertions, 1 deletions
diff --git a/nixos/modules/services/continuous-integration/hydra/default.nix b/nixos/modules/services/continuous-integration/hydra/default.nix
index fa550f68b33..57f592a2e55 100644
--- a/nixos/modules/services/continuous-integration/hydra/default.nix
+++ b/nixos/modules/services/continuous-integration/hydra/default.nix
@@ -328,7 +328,7 @@ in
           IN_SYSTEMD = "1"; # to get log severity levels
         };
         serviceConfig =
-          { ExecStart = "@${cfg.package}/bin/hydra-queue-runner hydra-queue-runner -v --option build-use-substitutes ${if cfg.useSubstitutes then "true" else "false"}";
+          { ExecStart = "@${cfg.package}/bin/hydra-queue-runner hydra-queue-runner -v --option build-use-substitutes ${boolToString cfg.useSubstitutes}";
             ExecStopPost = "${cfg.package}/bin/hydra-queue-runner --unlock";
             User = "hydra-queue-runner";
             Restart = "always";