diff --git a/amboar/obmc-scripts/dbus-pcap/dbus-pcap b/amboar/obmc-scripts/dbus-pcap/dbus-pcap
index 354dbc4..17a4f57 100755
--- a/amboar/obmc-scripts/dbus-pcap/dbus-pcap
+++ b/amboar/obmc-scripts/dbus-pcap/dbus-pcap
@@ -183,7 +183,9 @@
         remaining = bytes(self.stream)
         offset = self.offset
         self.offset += len(remaining)
-        assert self.offset - self.stash[1] == len(self.stash[0])
+        assert self.offset - self.stash[1] == len(self.stash[0]), \
+                ("(self.offset - self.stash[1]): %d, len(self.stash[0]): %d"
+                    % (self.offset - self.stash[1], len(self.stash[0])))
         return remaining, offset
 
     def dump(self):