diff --git a/src/toolbox_scs/routines/boz.py b/src/toolbox_scs/routines/boz.py
index bcdc92c1f6d17c7c20dc104a0334c798015102b5..27333bd499f950fc147ff5e837285119857cb131 100644
--- a/src/toolbox_scs/routines/boz.py
+++ b/src/toolbox_scs/routines/boz.py
@@ -92,8 +92,8 @@ class parameters():
             self.module, drop_intra_darks=True, persist=True)
 
         # make sure to rechunk the arrays
-        self.arr = self.arr.rechunk((100, -1, -1, -1))
-        self.arr_dark = self.arr_dark.rechunk((100, -1, -1, -1))
+        self.arr = self.arr.rechunk(('auto', -1, -1, -1))
+        self.arr_dark = self.arr_dark.rechunk(('auto', -1, -1, -1))
 
     def set_mask(self, arr):
         """Set mask of bad pixels.
@@ -473,7 +473,7 @@ def histogram_module(arr, mask=None):
     if mask is not None:
         w = da.repeat(da.repeat(da.array(mask[None, None, :, :]),
                 arr.shape[1], axis=1), arr.shape[0], axis=0)
-        w = w.rechunk((100, -1, -1, -1))
+        w = w.rechunk(arr.chunks)
         return da.bincount(arr.ravel(), w.ravel(), minlength=512).compute()
     else:
         return da.bincount(arr.ravel(), minlength=512).compute()