diff --git a/cross/ocaml.nix b/cross/ocaml.nix
index 62fd0776b..5132ff86e 100644
--- a/cross/ocaml.nix
+++ b/cross/ocaml.nix
@@ -239,9 +239,7 @@ in
 
       topkg = natocamlPackages.topkg.overrideAttrs (o:
         let
-          run = ''
-            ${natocaml}/bin/ocaml -I ${natfindlib}/lib/ocaml/${osuper.ocaml.version}/site-lib pkg/pkg.ml \
-          '';
+          run = "${natocaml}/bin/ocaml -I ${natfindlib}/lib/ocaml/${osuper.ocaml.version}/site-lib pkg/pkg.ml";
         in
         {
           selfBuild = true;
@@ -250,11 +248,7 @@ in
             inherit run;
           };
 
-          buildPhase = ''
-            runHook preBuild
-            ${run} build
-            runHook postBuild
-          '';
+          buildPhase = "${run} build";
 
           installPhase = ''
             if [ -z "''${selfBuild:-}" ]; then