I made a calibre plugin that generates real Print Replica KFX from any PDF, no Send to Kindle needed

Made a small calibre plugin for anyone who wants proper writable PDFs on a Kindle Scribe without going through Send to Kindle.

The Scribe writes on PDFs reliably in one case: Send to Kindle converts them to a "Print Replica" KFX behind the scenes. Sideloading a raw PDF over USB is hit or miss depending on your device/firmware, and even when it works, annotations often don't survive the transfer back to your computer and there's no email export.

This plugin builds that same Print Replica KFX locally through calibre. Select your PDFs, click a button, and calibre adds a proper KFX to each book, embedding the original PDF with correct page geometry so ink and zoom behave right. No Amazon account, nothing uploaded anywhere, and it batch-converts your whole library at once.

Not affiliated with Amazon, it just uses jhowell's KFX Output plugin for the final conversion step (you'll need that installed too).

Full writeup with more detail on MobileRead: https://www.mobileread.com/forums/showthread.php?p=4596577#post4596577

This is a first release so feedback's welcome