diff --git a/src/calibre/ebooks/metadata/plucker.py b/src/calibre/ebooks/metadata/plucker.py
index fabaa080d2..3f9513621d 100644
--- a/src/calibre/ebooks/metadata/plucker.py
+++ b/src/calibre/ebooks/metadata/plucker.py
@@ -44,8 +44,10 @@ def get_metadata(stream, extract_cover=True):
     author = None
     pubdate = 0
     for i in xrange(record_count):
-        type, = struct.unpack('>H', section_data[2+adv:4+adv])
-        length, = struct.unpack('>H', section_data[4+adv:6+adv])
+        try:
+            type, length = struct.unpack_from('>HH', section_data, 2 + adv)
+        except struct.error:
+            break
 
         # CharSet
         if type == 1:
diff --git a/src/calibre/ebooks/pdb/plucker/reader.py b/src/calibre/ebooks/pdb/plucker/reader.py
index 0d2ca6983c..4bc2ed988a 100644
--- a/src/calibre/ebooks/pdb/plucker/reader.py
+++ b/src/calibre/ebooks/pdb/plucker/reader.py
@@ -199,8 +199,10 @@ class SectionMetadata(object):
 
         adv = 0
         for i in xrange(record_count):
-            type, = struct.unpack('>H', raw[2+adv:4+adv])
-            length, = struct.unpack('>H', raw[4+adv:6+adv])
+            try:
+                type, length = struct.unpack_from('>HH', raw, 2 + adv)
+            except struct.error:
+                break
 
             # CharSet
             if type == 1: