No Python 2 service necessary! And it can also handle device authentication.

This is a work in progress!

Copy the media_player/firetv.py to your custom_components folder (custom_components/media_player/firetv.py).

media_player:
  - platform: firetv
    name: Fire TV 1
    host: 192.168.0.111

  - platform: firetv
    name: Fire TV 2
    host: 192.168.0.222
    adbkey: "/config/android/adbkey"

If you get a "Device authentication required, no keys available" error when trying to setup Fire TV, then you'll need to create an adbkey and add its path to your configuration. Follow the instructions on this page to connect to your Fire TV from your computer: Connecting to Fire TV Through adb.

Important! You must check the box that says "always allow connections from this device." ADB authentication in Home Assistant will only work using a trusted key.

Once you've successfully connected to your Fire TV via the command adb connect <ipaddress>, the files adbkey and adbkey.pub will be created on your computer. Copy these to your Home Assistant folder and add the path to the adbkey file to your configuration.

This is based on python-firetv by happyleavesaoc, and it depends on python-adb.