Originally Posted by gabrielscunha
This didn't work for me. After turning the wi-fi back on and opening the book, my Kindle automatically replaces its cover with Amazon's blank one.
You misunderstood me, I wasn't presenting a solution
I was saying that I'm having a problem similar to yours, but the covers only dissapear after I turn the wifi on, and this happens only with the books I've sent to kindle via calibre in the past 3 weeks, all the other books are fine, that's why I think it might have something to do with the current calibre version.