diff --git a/tools/lib/filereader.py b/tools/lib/filereader.py
index 4aec965f1a..15e618f649 100644
--- a/tools/lib/filereader.py
+++ b/tools/lib/filereader.py
@@ -1,4 +1,6 @@
 import os
+import requests
+
 from openpilot.tools.lib.url_file import URLFile
 
 DATA_ENDPOINT = os.getenv("DATA_ENDPOINT", "http://data-raw.comma.internal/")
@@ -8,6 +10,12 @@ def resolve_name(fn):
     return fn.replace("cd:/", DATA_ENDPOINT)
   return fn
 
+def file_exists(fn):
+  fn = resolve_name(fn)
+  if fn.startswith(("http://", "https://")):
+    return requests.head(fn, allow_redirects=True).status_code == 200
+  return os.path.exists(fn)
+
 def FileReader(fn, debug=False):
   fn = resolve_name(fn)
   if fn.startswith(("http://", "https://")):
diff --git a/tools/lib/logreader.py b/tools/lib/logreader.py
index 36cff0d724..36d099de50 100755
--- a/tools/lib/logreader.py
+++ b/tools/lib/logreader.py
@@ -17,7 +17,7 @@ from urllib.parse import parse_qs, urlparse
 
 from cereal import log as capnp_log
 from openpilot.tools.lib.openpilotci import get_url
-from openpilot.tools.lib.filereader import FileReader
+from openpilot.tools.lib.filereader import FileReader, file_exists
 from openpilot.tools.lib.helpers import RE
 from openpilot.tools.lib.route import Route, SegmentRange
 
@@ -84,15 +84,13 @@ def create_slice_from_string(s: str):
     return start
   return slice(start, end, step)
 
-def parse_slice(sr: SegmentRange):
-  route = Route(sr.route_name)
+def parse_slice(sr: SegmentRange, route: Route):
   segs = np.arange(route.max_seg_number+1)
   s = create_slice_from_string(sr._slice)
   return segs[s] if isinstance(s, slice) else [segs[s]]
 
-def comma_api_source(sr: SegmentRange, mode=ReadMode.RLOG):
-  segs = parse_slice(sr)
-  route = Route(sr.route_name)
+def comma_api_source(sr: SegmentRange, route: Route, mode=ReadMode.RLOG):
+  segs = parse_slice(sr, route)
 
   log_paths = route.log_paths() if mode == ReadMode.RLOG else route.qlog_paths()
 
@@ -102,35 +100,33 @@ def comma_api_source(sr: SegmentRange, mode=ReadMode.RLOG):
 
   return [(log_paths[seg]) for seg in segs]
 
-def internal_source(sr: SegmentRange, mode=ReadMode.RLOG):
-  segs = parse_slice(sr)
+def internal_source(sr: SegmentRange, route: Route, mode=ReadMode.RLOG):
+  segs = parse_slice(sr, route)
 
   return [f"cd:/{sr.dongle_id}/{sr.timestamp}/{seg}/{'rlog' if mode == ReadMode.RLOG else 'qlog'}.bz2" for seg in segs]
 
-def openpilotci_source(sr: SegmentRange, mode=ReadMode.RLOG):
-  segs = parse_slice(sr)
+def openpilotci_source(sr: SegmentRange, route: Route, mode=ReadMode.RLOG):
+  segs = parse_slice(sr, route)
 
   return [get_url(sr.route_name, seg, 'rlog' if mode == ReadMode.RLOG else 'qlog') for seg in segs]
 
 def direct_source(file_or_url):
   return [file_or_url]
 
-def auto_source(*args):
-  # Automatically determine viable source
-
+def check_source(source, *args):
   try:
-    identifiers = internal_source(*args)
-    _LogFileReader(identifiers[0])
-    return internal_source(*args)
+    files = source(*args)
+    assert all(file_exists(f) for f in files)
+    return True, files
   except Exception:
-    pass
+    return False, None
 
-  try:
-    identifiers = openpilotci_source(*args)
-    _LogFileReader(identifiers[0])
-    return openpilotci_source(*args)
-  except Exception:
-    pass
+def auto_source(*args):
+  # Automatically determine viable source
+  for source in [internal_source, openpilotci_source]:
+    valid, ret = check_source(source, *args)
+    if valid:
+      return ret
 
   return comma_api_source(*args)
 
@@ -173,10 +169,11 @@ class LogReader:
         return direct_source(identifier)
 
     sr = SegmentRange(parsed)
+    route = Route(sr.route_name)
     mode = self.default_mode if sr.selector is None else ReadMode(sr.selector)
     source = self.default_source if source is None else source
 
-    return source(sr, mode)
+    return source(sr, route, mode)
 
   def __init__(self, identifier: str | List[str], default_mode=ReadMode.RLOG, default_source=auto_source, sort_by_time=False, only_union_types=False):
     self.default_mode = default_mode
@@ -189,7 +186,6 @@ class LogReader:
     self.reset()
 
   def __iter__(self):
-    self.reset()
     for identifier in self.logreader_identifiers:
       yield from _LogFileReader(identifier)
 
diff --git a/tools/lib/tests/test_logreader.py b/tools/lib/tests/test_logreader.py
index a9769e5e63..74ee82d152 100644
--- a/tools/lib/tests/test_logreader.py
+++ b/tools/lib/tests/test_logreader.py
@@ -6,7 +6,7 @@ import pytest
 from parameterized import parameterized
 import requests
 from openpilot.tools.lib.logreader import LogReader, parse_indirect, parse_slice, ReadMode
-from openpilot.tools.lib.route import SegmentRange
+from openpilot.tools.lib.route import Route, SegmentRange
 
 NUM_SEGS = 17 # number of segments in the test route
 ALL_SEGS = list(np.arange(NUM_SEGS))
@@ -42,7 +42,8 @@ class TestLogReader(unittest.TestCase):
   def test_indirect_parsing(self, identifier, expected):
     parsed, _, _ = parse_indirect(identifier)
     sr = SegmentRange(parsed)
-    segs = parse_slice(sr)
+    route = Route(sr.route_name)
+    segs = parse_slice(sr, route)
     self.assertListEqual(list(segs), expected)
 
   def test_direct_parsing(self):
@@ -91,6 +92,14 @@ class TestLogReader(unittest.TestCase):
 
     self.assertEqual(qlog_len*2, qlog_len_2)
 
+  @pytest.mark.slow
+  def test_multiple_iterations(self):
+    lr = LogReader(f"{TEST_ROUTE}/0/q")
+    qlog_len1 = len(list(lr))
+    qlog_len2 = len(list(lr))
+
+    self.assertEqual(qlog_len1, qlog_len2)
+
 
 if __name__ == "__main__":
   unittest.main()