Alright,
First of all, sorry if my previous message was too harsh
I didn’t check the date.
Secondly, you might as well be on the screen where you need to do a secret gesture. Briefly tap and release with two fingers in the bottom right corner. Then quickly after this put and hold one finger in the same bottom right corner and swipe to the left.
Search for “kindle secret gesture”, there were a fee videos with it.
After that, you have options. Type in ;uzb command in the search and hit enter, then connect the cable, you will be able to access storage.
Why did you do demo_mode in the first place?
If this option doesn’t work, your only other option is nuking it: instead of your pin code, type 111222777 then OK. This will factory reset EVERYTHING, so all books you previously had will be deleted.