Well, I've been testing the method I pointed out in a previous post.
And the advance is as follows
1. It really works in a practical sense because it solves the problem and you can see the covers of your books not bought on amazon.
2. It works and is a solution so far, and they are not deleted.
To do this try the following
Restart the kindle
Then I synchronized it
It is connected to wifi
and the covers still persist.
3. According to lei in the league that I mentioned in the previous post
Amazon only does that with the new contents of the kindle and when finding a new content it proceeds to remove the cover, but not the previous content, so until now it does not check the covers of the books more than once
my 2cents