Since April 30, 2021, we no longer support Firefox on Amazon Fire TV or Echo Show. You are no longer able to install the app on FireTV or receive security updates starting since April 30, 2021. If you have set Firefox as your default browser on Echo Show, you are redirected to Amazon Silk for web browsing since April 30, 2021.
Alternatives to Firefox on Amazon devices
You can still browse the web on your Fire TV and Echo Show by using Amazon Silk. Just say “Alexa, open Silk.”