By "nothing" please expand on that.
Do me a favour and printout / screenie EXACTLY the output of
ls /mnt/us/extensions
or
ls /Media/Kindle/extensions
or whatever that location is called on your device when it is mounted on your PC or via via ssh
(however you are doing this)
I forget how to do that on windows but you get the idea...
Need a little bit more detail to be able to help.
Also final thought... just give
https://www.mobileread.com/forums/sho...&postcount=778 a look over and check that THAT is not the case here...
Much obliged.