diff --git a/pyulog/core.py b/pyulog/core.py
index 8d39115..257160c 100644
--- a/pyulog/core.py
+++ b/pyulog/core.py
@@ -607,7 +607,7 @@ def _find_sync(self, last_n_bytes=-1):
                 sync_seq_found = True
                 break
 
-            elif last_n_bytes != -1:
+            if last_n_bytes != -1:
                 # we read the whole last_n_bytes and did not find sync
                 break
 
@@ -784,4 +784,3 @@ def get_version_info_str(self, key_name='ver_sw_release'):
             elif version[3] < 255: type_str = ' (RC)'
             return 'v{}.{}.{}{}'.format(version[0], version[1], version[2], type_str)
         return None
-
diff --git a/pyulog/extract_gps_dump.py b/pyulog/extract_gps_dump.py
index 2ab2037..0bb29f0 100644
--- a/pyulog/extract_gps_dump.py
+++ b/pyulog/extract_gps_dump.py
@@ -7,6 +7,7 @@
 
 import argparse
 import os
+import sys
 
 from .core import ULog
 
@@ -55,7 +56,7 @@ def is_valid_directory(parser, arg):
 
     if len(data) == 0:
         print("File {0} does not contain gps_dump messages!".format(ulog_file_name))
-        exit(0)
+        sys.exit(0)
 
     gps_dump_data = data[0]
 
@@ -63,7 +64,7 @@ def is_valid_directory(parser, arg):
     field_names = [f.field_name for f in gps_dump_data.field_data]
     if not 'len' in field_names or not 'data[0]' in field_names:
         print('Error: gps_dump message has wrong format')
-        exit(-1)
+        sys.exit(-1)
 
     if len(ulog.dropouts) > 0:
         print("Warning: file contains {0} dropouts".format(len(ulog.dropouts)))