[kandwo]

I use Koreader on both my Hisense A5 Pro and Nova 3 and sync the progress between them. I recently started reading a book (zip compressed fb2) on my Nova 3. When I tried opening the same file on my A5 Pro Koreader shows the message "(no book information: not readable by engine)" in the file browser. When clicking on the file it displays "No reader engine for this file or invalid file."

Some of the zipped fb2 files show up just fine on the A5. All of the files work perfectly on the Nova 3.

I tried unzipping the file on the A5 and the resulting fb2 opened up just fine. But it wouldn't sync the progress with the still zipped fb2 file on my Nova 3, of course.

What could the reason for this be? I'm confused since I use the latest Koreader from F-droid on both devices and the same files.

EDIT: I thought the files might have corrupted somehow when being transferred to the A5, but they opened up just fine in Alreader X, so that doesn't seem to be it either..