Phone home for sure since I suffered from the minor nuisance:
https://blog.the-ebook-reader.com/2020/05/28/kindles-how-to-fix-disappearing-book-covers-issue/
Easy fix in Calibre since just reconnect after the sync.
The bottomline is Amazon does not block side loaded epub/mobi.
Phone home for sure since I suffered from the minor nuisance:
https://blog.the-ebook-reader.com/2020/05/28/kindles-how-to-fix-disappearing-book-covers-issue/
Easy fix in Calibre since just reconnect after the sync.
The bottomline is Amazon does not block side loaded epub/mobi.