diff --git a/default.nix b/default.nix
index 8267fd3..e858c98 100644
--- a/default.nix
+++ b/default.nix
@@ -4,12 +4,7 @@ pkgs.stdenv.mkDerivation {
   version = "1.0";
 
   #src = ./db-main;
-  src = builtins.fetchurl {
-    url = "https://projects.info.unamur.be/dbmain/files/dbm-1102-linux-amd64-setup.tar.gz";
-    sha256 = "8f61e6069337dc734ac6f886b224329ec943cd4dafbd888611bd806373cb3296";
-  };
-
-  umpackCmd = "tar -xzf $src";
+  src = builtins.fetchTarball "https://projects.info.unamur.be/dbmain/files/dbm-1102-linux-amd64-setup.tar.gz";
 
   nativeBuildInputs = [
     pkgs.makeWrapper