diff --git a/src/cal_tools/jungfrau/jungfrau_ff.py b/src/cal_tools/jungfrau/jungfrau_ff.py
index 8af48745f100302103c3820b03d7a4dd2630f448..c4f6d33b7854f4d44ee95716da512cb68a2fae11 100644
--- a/src/cal_tools/jungfrau/jungfrau_ff.py
+++ b/src/cal_tools/jungfrau/jungfrau_ff.py
@@ -68,8 +68,8 @@ def chunk_multi(data, block_size):
         for j in range(0, cols, chunk_cols):
             chunk = data[
                 ...,
-                i:min(i+chunk_rows, rows),
-                j:min(j+chunk_cols, cols)
+                i: i+chunk_rows,
+                j: j+chunk_cols
             ]
             chunks.append(chunk)
 
@@ -96,7 +96,7 @@ def fill_histogram(image_data, histogram_bins):
     if not isinstance(image_data, np.ndarray):
         raise TypeError("Expected imgs numpy ndarray type.")
 
-    if image_data.ndim < 4:
+    if image_data.ndim != 4:
         raise ValueError("Expected 4D imgs array.")
 
     n_cells, n_rows, n_cols = image_data.shape[1:]
@@ -218,7 +218,7 @@ def rebin_histo(hist, bin_centers, rebin_factor):
     x_out = bin_centers[::rebin_factor]
 
     h_out = np.sum(
-        hist[:len(hist) - (len(hist) % rebin_factor)].reshape(-1, rebin_factor),  # noqa
+        hist.reshape(-1, rebin_factor),
         axis=1,
     )
     x_out = bin_centers[::rebin_factor]