diff --git a/edosl0util/stream.py b/edosl0util/stream.py
index f06ac8491dfa52e0b46581bdda164922c61d2f07..2c7c075ed6b6ea949e0ff0b9223a08991fc54312 100644
--- a/edosl0util/stream.py
+++ b/edosl0util/stream.py
@@ -31,10 +31,9 @@ class PacketTooShort(Error):
     After this error occurs the stream is no longer usable because data offsets
     are no longer reliable.
     """
-    def __init__(self, header=None, offset=None):
-        self.offset = offset
+    def __init__(self, header=None):
         self.primary_header = header
-        self.args = (self.offset, self.primary_header)
+        self.args = (self.primary_header,)
 
 
 class NonConsecutiveSeqId(Error):
@@ -49,7 +48,6 @@ class SimpleStream(object):
     """
     def __init__(self, fobj):
         self.fobj = fobj
-        self.offset = fobj.tell()
 
     def __iter__(self):
         return self
@@ -63,14 +61,13 @@ class SimpleStream(object):
         if not buf:
             raise StopIteration()
         if len(buf) < psize:
-            raise PacketTooShort(header=None, offset=self.offset)
+            raise PacketTooShort(header=None)
         h1 = PrimaryHeader.from_buffer_copy(buf)
         # read user data
         size = h1.data_length_minus1 + 1
         buf = self.fobj.read(size)
         if len(buf) < size:
-            raise PacketTooShort(header=h1, offset=self.offset)
-        self.offset += (psize + size)
+            raise PacketTooShort(header=h1)
         return h1, buf
 
 
diff --git a/edosl0util/trunc.py b/edosl0util/trunc.py
index a68402b872cbf2af4d7484d54fd26e7f78d82d61..7d944b2e8e143b9463a89f8305a96de2e069a543 100644
--- a/edosl0util/trunc.py
+++ b/edosl0util/trunc.py
@@ -6,7 +6,8 @@ from edosl0util.stream import PacketStream
 
 
 def trunc_stream(stream, start, end):
-    stream.seek(start)
+    stream.seek_to(start)
+    stream.seek_to_next_stamp()
 
     pkt = stream.next()
     while pkt.stamp <= end:
diff --git a/setup.py b/setup.py
index d12c555d9562a00d74f5d1b36b513dcd24281e0a..acc5f6ddc460bee355c26c65dd68b0e8350cb04e 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@ setup(
     author='Bruce Flynn',
     author_email='brucef@ssec.wisc.edu',
     description='Utilities for working with EDOS L0 PDS files',
-    version='0.4',
+    version='0.4.1',
     zip_safe=False,
     packages=find_packages(),
     install_requires=[