These notes describe the process on the Kindle 3, but some of the information is transferable, and I’ve also taken very similar actions on a Kindle 4 and a Kindle 5. While you can install the screen-saver hack and even the fonts hack, which allows you to take control of your font customisation if you so wish, you’re much better off installing KOR eader, as is covered later in this guide, which completely overhauls the experience and gives you the aforementioned options in addition to many more and a much nicer overall experience. You can grab the install from NiLuJe’s Snapshot thread and then follow the installation guide halfway down the MKK page to install it.