diff --git a/flake.nix b/flake.nix
index aa1a67f3..6e33d442 100644
--- a/flake.nix
+++ b/flake.nix
@@ -48,8 +48,8 @@
           keepContentsDirlinks = true;
           # This adds a correct timestamp, however breaks binary reproducibility
           created = "now";
-          extraCommands = ''
-            mkdir -m 1777 tmp
+          runAsRoot = ''
+            chmod 1777 /tmp
           '';
           config = {
             Entrypoint = [ "polykey" ];
diff --git a/scripts/npmDepsHash.sh b/scripts/npmDepsHash.sh
index ef0b99bb..8f8bd340 100755
--- a/scripts/npmDepsHash.sh
+++ b/scripts/npmDepsHash.sh
@@ -2,4 +2,4 @@
 
 newHash=$(nix-shell -p prefetch-npm-deps --run "prefetch-npm-deps ./package-lock.json")
 
-echo $newHash > ./npmDepsHash
+echo "$newHash" > ./npmDepsHash