diff --git a/km3io/daq.py b/km3io/daq.py
index 084e751533ea65327bf1c4cbcafae58003a03363..e9dba8162f3f7272ed84dedd5a80f2d9981ff90e 100644
--- a/km3io/daq.py
+++ b/km3io/daq.py
@@ -140,11 +140,11 @@ class DAQTimeslices:
             if len(headers) == 0:
                 continue
             superframes = tree[b'vector<KM3NETDAQ::JDAQSuperFrame>']
+            hits_dtype = np.dtype([("pmt", "u1"), ("tdc", "<u4"),
+                                   ("tot", "u1")])
             hits_buffer = superframes[
                 b'vector<KM3NETDAQ::JDAQSuperFrame>.buffer'].lazyarray(
-                    uproot.asjagged(uproot.astable(
-                        uproot.asdtype([("pmt", "u1"), ("tdc", "u4"),
-                                        ("tot", "u1")])),
+                    uproot.asjagged(uproot.astable(uproot.asdtype(hits_dtype)),
                                     skipbytes=6),
                     basketcache=uproot.cache.ThreadSafeArrayCache(
                         TIMESLICE_FRAME_BASKET_CACHE_SIZE))