PearlsSwineEtcUse Kindle as an Epub Reader?
Phone home for sure since I suffered from the minor nuisance:
blog.the-ebook-reader.com/…/kindles-how-to-fix-di…
Easy fix in Calibre since just reconnect after the sync.
The bottomline is Amazon does not block side loaded epub/mobi.
Kindles: How to Fix Disappearing Book Covers Issue | The eBook Reader Blog
Amazon recently changed how cover art works with sideloaded content on Kindle devices and it has caused an issue that makes book covers disappear. Basically if the book doesn't have a valid ASIN that corresponds with Amazon's server then the cover image will get overwritten with a generic thumbnail image. Some workarounds were discovered, like