[Metadata Writer Plugin] Kindle Real ASIN: covers for sideloaded books on Kindle

[papisuso]

Kindle Real ASIN makes books you send to a Kindle with calibre show up as Books (not Docs) with their cover.

The problem
On newer Kindles that connect over MTP, AZW3 books sent with calibre show up as Books but often without a cover. For a Book (cdetype EBOK) the Kindle takes the cover either from a thumbnail in system/thumbnails or from Amazon, using the ASIN in the file. calibre writes its own book UUID as the ASIN (EXTH 113), so the Kindle cannot fetch the cover, and on these devices the thumbnail route does not help either.

What the plugin does
It replaces calibre's built-in MOBI metadata writer for AZW3, MOBI and AZW. It writes the same metadata as calibre and, if the book has an Amazon identifier that looks like a Kindle ASIN (B + 9 characters), it writes that ASIN into EXTH 113 and 504 with cdetype EBOK. With Wi-Fi on, the Kindle downloads the cover from Amazon and the book stays a Book.

It runs whenever calibre writes metadata into a file: Send to device and Embed metadata.

Use

1. Make sure the book has an Amazon id in Edit metadata > Ids, e.g. amazon:B0XXXXXXXX (or amazon_de:, amazon_es:, mobi-asin:). Download metadata often adds it.
2. Convert to AZW3 if needed.
3. Send to device over USB.
4. Keep Wi-Fi on. The cover shows up after a short while.

Settings (optional)
Preferences > Plugins > Kindle Real ASIN > Customize plugin: your Amazon store(s) in order of preference, e.g. "es, de" or "co.uk".

Limits

• Tested so far on a Kindle Paperwhite Signature Edition (MTP) with calibre 9.18 on macOS. Reports from other models are very welcome.
• Books without a Kindle edition on Amazon still get no cover.
• Books marked with calibre's Personal Doc tag stay personal documents.
• KFX is not handled.
• Books already on the Kindle are not changed. Send them again.

Install
Download the zip attached to this post, then Preferences > Plugins > Load plugin from file, restart calibre.

Source and README: https://github.com/papisuso/calibre-kindle-real-asin
License: GPL v3

Version History

Spoiler:

1.1.0 (2026-11-14): First public release. Configurable store order, personal doc tag respected.