[Kindle Fire HDX 7" & 8.9" General] oOBubbleBoyOo:
WARNING: NEW UPDATE (14/13.3.2.3) ROLLING OUT, I ADVISE NOT USING THESE METHODS FOR NOW IN RISK OF ACCIDENTALLY UPDATING. STICK TO AIRPLANE MODE AND WIFI OFF FOR NOW. USE THESE METHODS AT YOUR OWN RISK. Thanks to Faznx92 for the update notice.

Alright guys, I believe I have found a decent way on how to prevent Amazon updates while using the device. Some may have done this but maybe haven't mentioned these methods because I have never found a thread on this. If you have other ways to block Amazon's updates, please don't hesitate to post! This is to help you and me, all ideas are welcome :)

1. Blocking WiFi

I found a neat app on the Google Play store that allows you to block inbound and outbound WiFi transmissions, (or you could just turn off the WiFi yourself, but hey, are you fast enough?). It is called "Net Blocker". Upon starting the application, select every Amazon application (including settings, which is the gear icon) and check the mobile and wifi boxes. You should see the wifi and mobile icons disappear next to the application names. One more important application to disable is your current LAUNCHER. This way the WiFi/Mobile Data is disabled when using the launcher. The WiFi/Mobile Data will be re-enabled if you go on an application that isn't blocked. EX: If you are using Silk Browser (with WiFi/Mobile Data enabled), and hit the home screen (with launcher WiFi/Mobile Data disabled), the WiFi/Mobile Data will disable on its own, since you blocked the launcher.

2. WiFi Timer

Amazon likes to be a butthole and likes to update while you sleep. This app is called "Wifi Timer", which is on Google Play, that allows you to set a schedule when you want your WiFi on or off (or you could just turn off your kindle and not use it). Just add a schedule, select all the days of the week, and where it says "stop wifi" set the time whatever time you go to sleep. It should disable the WiFi at that time if not already disabled by Net Blocker. (Just to be really safe, set a bunch of schedules during the night to disable WiFi) (Also I don't know much about what happens in the background during the update process, but if the application is still running in the background, I'm sure that the WiFi would turn off during the downloading process if your schedule turns the WiFi off. But Amazon probably closes all the running applications before starting the update process so that nothing interferes with it.

I must state that these methods are a tad bit risky (for now). A big flaw in these WiFi methods is the Kindle's feature on remembering the WiFi's password, EX: When the Kindle Update starts, it will search for your saved WiFi and automatically connect with the password it remembered. So if we can find a WiFi manager application that will purposely forget the WiFi's password so that you have to always put in the password every time you want to log in, then that will fix the flaw. Again, Amazon will probably prevent that type of application from running in danger of stopping the updates.

These applications work on the kindle. For those who want to directly download the applications from Google Play use Evozi's Apk Downloader (search for it on Google). When you get to the website copy and paste the Google Play address of the application and click download.

3. DIY Zip Dummy

There has been some debate on this method, I don't recommend this because I'm pretty sure that the kindle has it's own partition for system updates. Basically in this method you fill up you kindle's memory with a zip file full of memory to take up space "preventing" the kindle from installing anything else because of insufficient space. But I wouldn't do this, unless you do it for testing and you want to risk yourself into getting an update.