Save Your Hack Files
From MobileRead
YOU MAY NEED TO REMOVE ANY AND ALL HACKS BEFORE YOUR KINDLE CAN BE UPDATED BY AMAZON, PLEASE BE SURE TO KEEP THE INSTALL AND UNINSTALL FILES IN A PLACE WHERE YOU CAN FIND THEM EASILY.
I personally keep a copy of all the hacks I'm currently using on my Kindle. I unzip the files and store them in the appropriate folders. If you have a lot of books on your Kindle this may not work for you but you should keep them altogether in one (or two) place(s) so that you can easily uninstall them if needed. I also keep a pdf copy of the installation instructions on my Kindle.