diff --git a/pkgs/development/ocaml-modules/ppx_blob/default.nix b/pkgs/development/ocaml-modules/ppx_blob/default.nix
index 3ee11e13618c..1406eab9ba7b 100644
--- a/pkgs/development/ocaml-modules/ppx_blob/default.nix
+++ b/pkgs/development/ocaml-modules/ppx_blob/default.nix
@@ -7,14 +7,14 @@
   ppxlib,
 }:
 
-buildDunePackage rec {
+buildDunePackage (finalAttrs: {
   pname = "ppx_blob";
   version = "0.9.0";
 
   minimalOCamlVersion = "4.08";
 
   src = fetchurl {
-    url = "https://github.com/johnwhitington/${pname}/releases/download/${version}/ppx_blob-${version}.tbz";
+    url = "https://github.com/johnwhitington/ppx_blob/releases/download/${finalAttrs.version}/ppx_blob-${finalAttrs.version}.tbz";
     sha256 = "sha256-8RXpCl8Qdc7cnZMKuRJx+GcOzk3uENwRR6s5uK+1cOQ=";
   };
 
@@ -27,4 +27,4 @@ buildDunePackage rec {
     description = "OCaml ppx to include binary data from a file as a string";
     license = lib.licenses.unlicense;
   };
-}
+})