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DNSB · 06-25-2025, 10:14 PM

Kindlegen generates a dual-mobi file which contains both KF7/mobi and KF8/azw3 format ebooks. You can use the KindleUnpack plugin for calibre to split the two formats into separate files. The penalty for this is that the output file size is close to 100% larger than a single format mobi or KF8/azw3 ebook.

If you copy a dual-mobi file to your PW, it will use the KF8/azw3 ebook.

As for your sample cover thumbnails? The cover shows up on a document while the EBOK does not show a cover image. This is more or less normal since an EBOK ebook will fetch it's cover thumbnails from Amazon which may require a registered device so this will not work for you since you have stated that your Kindle is not registered. calibre does have a workaround for this that works on non-MTP Kindles only since Amazon blocks access to the cover thumbnails directory on their MTP devices. If you are converting to azw3 using calibre, you could enable sharing using Facebook to create a PDOC cdetype or use an external utility to convert EBOK to PDOC for MTP devices.

06-25-2025, 10:14 PM	#8
DNSB Bibliophagist Posts: 46,712 Karma: 169712580 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	Kindlegen generates a dual-mobi file which contains both KF7/mobi and KF8/azw3 format ebooks. You can use the KindleUnpack plugin for calibre to split the two formats into separate files. The penalty for this is that the output file size is close to 100% larger than a single format mobi or KF8/azw3 ebook. If you copy a dual-mobi file to your PW, it will use the KF8/azw3 ebook. As for your sample cover thumbnails? The cover shows up on a document while the EBOK does not show a cover image. This is more or less normal since an EBOK ebook will fetch it's cover thumbnails from Amazon which may require a registered device so this will not work for you since you have stated that your Kindle is not registered. calibre does have a workaround for this that works on non-MTP Kindles only since Amazon blocks access to the cover thumbnails directory on their MTP devices. If you are converting to azw3 using calibre, you could enable sharing using Facebook to create a PDOC cdetype or use an external utility to convert EBOK to PDOC for MTP devices. Last edited by DNSB; 06-25-2025 at 10:20 PM.