Comment by a10c

Depending on your firmware version, most jailbreak guides will have you either create an empty directory with the same name as the OTA firmware file (causing any OTA downloads to fail) or install an extension called `renameotabin` which renames the binaries responsible for performing the update, rendering them inaccessible.

source: https://kindlemodding.org/jailbreaking/post-jailbreak/disabl...