Originally Posted by DoctorOhh
Dragging the html index page (or TOC) to calibre should grab up all extra files the index points to and combine them into 1 zip file.
I tried this now, and the zip file was restructured compared to the original: all HTML files were on the same level. So I hopefully tried a new zip->epub conversion.
But the resulting ePub still fails to open on the PRS-T1. It just exits back to the menu, showing this ePub as the most recently read document.