Content What distinguishes a Kindle "Doc" from a "book"

[pmorris]

I've been using Calibre to prepare books for my Kindle for quite a few years now. I use Calibre to do my editing in epub format, then convert to AZW3 (now—although when I started it was PRC, then Mobi, etc). All books are copied to the Kindle via USB. Something that has puzzled me for years is that occasionally instead of the document being recognized by the various Kindles as a book, it is recognized as a document. When I go back into edit and try to figure out what about this document is different, I see nothing to explain what was wrong, so I make a few minor modifications, convert again and the document shows up as a book. Rarely, I have been unable to edit the problem away and I am unable to get the Kindle to see the document as a book.

Does anyone know what piece of code is responsible for the distinction, but obviously there has to be a flag somewhere...

TIA

[shamanNS]

The value for "cdetype" (exth record #501) in EXTH Header of a mobi file. "EBOK" vs "PDOC" as a value.
Probably the easiest way to change that would be using Mobi Meta Editor (= standalone app) or Quality Check Calibre plugin.

[pmorris]

Thanks!