diff --git a/src/pineko/theory.py b/src/pineko/theory.py
index c274ce5e..899d8f66 100644
--- a/src/pineko/theory.py
+++ b/src/pineko/theory.py
@@ -396,7 +396,7 @@ def fk(self, name, grid_path, tcard, pdf):
             if not np.isclose(xif, 1.0):
                 check_scvar_evolve(grid, max_as, max_al, check.Scale.FACT)
         # loading ekos to produce a tmp copy
-        with eko.EKO.edit(eko_filename) as operators:
+        with eko.EKO.read(eko_filename) as operators:
             eko_tmp_path = operators.paths.root.parent / "eko-tmp.tar"
             operators.deepcopy(eko_tmp_path)
         with eko.EKO.edit(eko_tmp_path) as operators: