[JimmXinu]

Originally Posted by Tanjamuse

If I copy the following into the metadata-column can you add a tweak or something that would let Calibre sort it out on its own?

That doesn't change the issues previously mentioned, it just moves them to a different place.

Originally Posted by ILB

It´s as baggins41 said: I want to avoid re-downloading the book I already have (to avoid unnecessary traffic on the site) or in case the original story no longer exists because than it gets an error and no updated title page.
If there is another way to “update” title page without downloading the book again from the site that would be enough for me.

But can I use Calibre's built-in metadata jacket to add custom columns (which I maintain manually after downloading) to my title page?
And how do I update my book to do this?

Calibre's Polish feature has an option for add/update (and one for remove) 'metadata jacket'. The jacket is placed directly after the cover (if present). It does not effect the FFF title page, nor does it appear in the TOC like FFF title page does in multi-chapter books.

You can customize it by copying the default jacket template directory to your personal resources dir and then editing the files. The manual page explains it, but it may be a little out of date as for me the source dir is C:\Program Files\Calibre2\app\resources\jacket . Custom columns can be added by using _ instead of #. For #genre:

        <div>
          <p class="cbj_label">{_genre_label}:</p>
          <p class="cbj_content">{_genre}</p>
        </div>

FFF on update will discard the jacket file. But FFF already has an option to invoke the Polish option to smarten punctuation and I would be willing to add a similar option to automatically call Polish update jacket.

UPDATE: Calling Polish to update jacket might be more difficult than that--there are some 'interesting' interactions between conversion and jacket I would need to explore more.

(BTW, note that if you use Polish to add/update cover page, it will name the cover page file titlepage.xhtml. FFF's title page (title_page.xhtml) is unchanged.)