[davidfor]

Originally Posted by BobC

It appears from what you found in the manifest that somewhere in the process of adding a Cover page the EPUB got screwed.

I went back to first principles and deleted from Calibre anything other than the original .prc book then converted that, complete with split on chapters TOC etc. At this stage I had a customised cover set in Calibre. When I uploaded that version the problem persisted (though the manifest in the EPUB looked o.k).

I then removed the customised cover from within Calibre and re-built the book with no cover. When I transferred that everything was fine with the .kepub.epub.

A conversion in calibre will fix it, or opening in Sigil and saving will as well.

So it looks like adding the cover using the "Generate Custom Cover" is where the problem originates. Not sure just why as I have another one that worked fine with a custom cover.

You mean with the "Generate Cover" plugin? I just had a play with a book in my library and can't get it to do the same thing. It is probably something unusual about the starting file.

Originally Posted by BobC

I made the mistake of trying to examine the EPUB with Sigil - in that the manifest part of content.opf looked o.k. However when I then expanded the EPUB with 7-Zip and looked at the content file with a text editor I saw what you meant.

Moral of the story - don't believe what you see ! - check.

I don't know how many times I have done that. The Tweak books option in calibre gets a work-out because of this.

Originally Posted by BobC

I only encountered the problem when I uploaded as .kepub.epub - it appears that the renderer for simple EPUBs is more forgiving over this issue than the one for KEPUBs so the already broken EPUB displayed o.k. That's why I need to give my library a check before loading any more, not because I thought there was a problem with the extended driver.

It would be interesting to see the epub loaded in an older firmware. I know that Kobo have done work on the handling of bad epubs in the last couple of firmware versions, but I don't know what they have actually fixed.

I did think the problem was in the original EPUB conversion, possibly because this had been done a couple of years ago with an earlier version of Calibre but never though that it would be cover related.

Well, it isn't actually the cover. It is where the files are and the manifest. I think it would have failed if any of the files had been in a parent directory. But, it might also have been visible because the cover page is the first page the reader shows.