[eschwartz]

Under Preferences ==> Output Options==> MOBI Output, set the PDOC tag (default is [PDOC]) to [EBOK]. calibre will then stop updating the cdetype to PDOC on the fly during send-to-device.

If you need to add the ASIN, Quality Check PI can check your library for any book that are missing ASINs and/or add the mobi-asin/asin/amazon/uuid identifier (in descending order of priority) as the ASIN. (This fix is needed so books show up properly on the Fire, IIRC.)