PW3 Stuck in demo mode after Winterbreak

[Mobilista]

Hello,
yesterday I tried jailbreaking my Kindle (5.16.2.1.1) using Winterbreak. I used the guide on kindlemodding.org and followed it to the letter.
Winterbreak and the hotfix did install normally as far as I could tell, however I ran into issues when trying to install KUAL. Specifically, nothing happened when typing ;log mrpi (or any other command) into the search bar.
I copied the "Update_KUALBooklet_HDRepack.bin" into the root folder and tried updating the kindle again as is suggested by the troubleshooting page (https://kindlemodding.org/jailbreaki...ing-kual-mrpi/), however I wasn't able to. After restarting the settings tab and the one above or under it was greyed out. I left it at that and went to sleep.

Today I started it again, however it is stuck in demo mode. There are only three fields I can enter information in (storeName, storeID and postal code), and I'm unable to navigate anywhere else. It is a german model if that matters. Restarting it brings me to the same page, and the computer doesnt show it as a drive anymore.
I'm kind of at my wits end here and hope someone here has some pointers on how I could save this piece of garbage from becoming literal garbage.