Installing Fresh Android OS I have Amazon fire tablet. I want to install fresh android 4.4 or above. Is there any step by step instruction available somewhere or how do I do this?
First you have to know which OS your tablet is running before you do anything. These tablets normally run Amazon Fire OS.

Amazon wanted to create its own operating system for its tablets. Rather than starting from scratch, Amazon takes that Android AOSP code and modified it to create “Fire OS.

But you can try your luck here..XDA Amazon Fire Forum