diff --git a/pkgs/build-support/fetchdarcs/default.nix b/pkgs/build-support/fetchdarcs/default.nix
index 6073efec2815..320b201f2853 100644
--- a/pkgs/build-support/fetchdarcs/default.nix
+++ b/pkgs/build-support/fetchdarcs/default.nix
@@ -1,21 +1,23 @@
 {stdenvNoCC, darcs, cacert, lib}:
 
 lib.makeOverridable (
-{ url
-, rev ? null
-, context ? null
-, sha256 ? ""
-, name ? "fetchdarcs"
-}:
+  lib.fetchers.withNormalizedHash { } (
+    { url
+    , rev ? null
+    , context ? null
+    , outputHash ? lib.fakeHash
+    , outputHashAlgo ? null
+    , name ? "fetchdarcs"
+    }:
 
-stdenvNoCC.mkDerivation {
-  builder = ./builder.sh;
-  nativeBuildInputs = [cacert darcs];
+    stdenvNoCC.mkDerivation {
+      builder = ./builder.sh;
+      nativeBuildInputs = [cacert darcs];
 
-  outputHashAlgo = "sha256";
-  outputHashMode = "recursive";
-  outputHash = sha256;
+      inherit outputHash outputHashAlgo;
+      outputHashMode = "recursive";
 
-  inherit url rev context name;
-}
+      inherit url rev context name;
+    }
+  )
 )