@Kelzanelie:
Once you've got ameho's file, you can forget the Chinese, everything you need to know is in the quote.
Aletrnatively, since your device is jailbroken, you can do it with dsmid's file:
https://www.mobileread.com/forums/sho...4&postcount=23
Download the old update.zip attachment, extract it in the USB root of your device, and put the official update for the version you want to downgrade to in the update folder that was extracted. Eject, "Update Your Kindle", you should get a first nearly instantaneous update process, and then the real full update.