How to prevent Calibre from converting or modifying ePub?

[Iced_Eagle]

Hey all,

For KOReader progress sync to work properly between devices, the file needs to be binary identical. I'm trying to find a way where Calibre will simply take the EPUB that it has and copy it to the corresponding device without touching the EPUB to do any sort of device specific change to it. I've tried doing a Convert locally, but even the ePub it makes is still slightly binary different to what it sends to the Kobo.

My setup is I have my Calibre library sync'd to the cloud, where my Android device pulls directly from the cloud to get the epub's. My Kobo Libra I plug in via USB and use Calibre's Send To Device function to upload any books that are missing. For whatever reason, Calibre will always edit the ePub in some way when it sends it over to the Kobo, thus breaking progress sync between devices. I have the Page Setup set to Tablet/Default Profile. I have all KePub/Kobo specific plug-ins disabled.

Anyone have any ideas of what else I can look at in Calibre?

[kovidgoyal]

If you dont want metadata updated in epubs disable the epub metadata writer plugin in preferences->Plugins