diff --git a/neo/rawio/neuralynxrawio.py b/neo/rawio/neuralynxrawio.py
index c18fd8ee8..423b49452 100644
--- a/neo/rawio/neuralynxrawio.py
+++ b/neo/rawio/neuralynxrawio.py
@@ -305,7 +305,7 @@ def _get_analogsignal_chunk(self, block_index, seg_index, i_start, i_stop, chann
 
         block_start = i_start // BLOCK_SIZE
         block_stop = i_stop // BLOCK_SIZE + 1
-        sl0 = i_start % 512
+        sl0 = i_start % BLOCK_SIZE
         sl1 = sl0 + (i_stop - i_start)
 
         if channel_indexes is None:
@@ -483,18 +483,13 @@ def read_ncs_files(self, ncs_filenames):
             if self.use_cache:
                 self.add_in_cache(lost_indexes=lost_indexes)
 
-        gap_candidates = np.unique([0]
-                                   + [data0.size]
-                                   + (gap_indexes + 1).tolist()
-                                   + lost_indexes.tolist())  # linear
+        gap_candidates = np.unique(np.concatenate(([0],
+                                                   gap_indexes + 1,
+                                                   lost_indexes + 1,
+                                                   [data0.size])))
 
         gap_pairs = np.vstack([gap_candidates[:-1], gap_candidates[1:]]).T  # 2D (n_segments, 2)
 
-        # construct proper gap ranges free of lost samples artifacts
-        minimal_segment_length = 1  # in blocks
-        goodpairs = np.diff(gap_pairs, 1).reshape(-1) > minimal_segment_length
-        gap_pairs = gap_pairs[goodpairs]  # ensures a segment is at least a block wide
-
         self._nb_segment = len(gap_pairs)
         self._sigs_memmap = [{} for seg_index in range(self._nb_segment)]
         self._sigs_t_start = []
@@ -521,13 +516,13 @@ def read_ncs_files(self, ncs_filenames):
                 if chan_uid == chan_uid0:
                     ts0 = subdata[0]['timestamp']
                     ts1 = subdata[-1]['timestamp'] \
-                            + np.uint64(BLOCK_SIZE / self._sigs_sampling_rate * 1e6)
+                            + np.uint64(subdata[-1]['nb_valid'] / self._sigs_sampling_rate * 1e6)
                     self._timestamp_limits.append((ts0, ts1))
                     t_start = ts0 / 1e6
                     self._sigs_t_start.append(t_start)
                     t_stop = ts1 / 1e6
                     self._sigs_t_stop.append(t_stop)
-                    length = subdata.size * BLOCK_SIZE
+                    length = (subdata[:-1].size * BLOCK_SIZE) + int(subdata[-1]['nb_valid'])
                     self._sigs_length.append(length)