For Kindles to offer a "Go to… TOC" menu (in Kindles that have such menu at all), Kindle Publishing Guidelines (2014.2) state:
3.3.3 TOC Guideline 3: HTML TOC Must Be Referenced
To enable the customer to jump to the TOC from the Kindle menu, the OPF file must reference the TOC from a TOC guide item or the navigation html file must reference a TOC in a landmarks nav element. […]
Here is an example of a landmarks nav element for a TOC:
<nav epub:type="landmarks">
<ol>
<li><a epub:type="toc" href="toc.html">Table of Contents</a></li>
</ol>
</nav>
While that will work for flowing layout books, for some obscure reason fixed layout books (FXL) have the additional unstated requirement that such reference has to point specifically to the toc nav element.
For Kindles to offer a "Go to… TOC" menu (in Kindles that have such menu at all), Kindle Publishing Guidelines (2014.2) state:
While that will work for flowing layout books, for some obscure reason fixed layout books (FXL) have the additional unstated requirement that such reference has to point specifically to the
toc
nav element.or else the "Go to… TOC" button will remain grayed out.