[KevinH]

Hi Kovid,

Here is what Mobiunpack says about your test.mobi file:

Unpacking Book ...
number of sections 6

Section Number, Starting Offset
0, 128
1, 2580
2, 2754
3, 2756
4, 2792
5, 2836

# Prints this just before it parses the exth header info
going to load section 0 now
loading section 0
before: 128 and after: 2580

# Offsets within this section
book title offset 384
offset to start of extended header 248
extended header length 132
extended header num_items 5

# Metadata keys and values stored in exth
Creator -> Unknown
Updated Title -> t
ASIN -> fa943046-2dcc-4be7-8ac0-888ef7e626ae
501 -> 45424f4b
Published -> 2011-04-15T16:50:21.482609+00:00

That means the length of my section 0 for this file is 2580 - 128 = 2452 bytes