diff --git a/src/toolbox_scs/routines/boz.py b/src/toolbox_scs/routines/boz.py
index 27333bd499f950fc147ff5e837285119857cb131..fbc2069c1b02c945c9b0b8e41667581c52067441 100644
--- a/src/toolbox_scs/routines/boz.py
+++ b/src/toolbox_scs/routines/boz.py
@@ -1246,7 +1246,7 @@ def nl_fit(params, domain):
     p0 = np.array([0]*N)
 
     # flat flat_field
-    ff = compute_flat_field_correction(params.rois, params.get_flat_field())
+    ff = compute_flat_field_correction(params.rois, params)
 
     fixed_p = (domain, params.nl_alpha, params.arr_dark, params.arr, params.tid,
         fitrois, params.get_mask(), ff, params.sat_level)