Its pretty rough, but if you’re craving some Community, it is possible to install Yahoo! Screen on your FireTV. This quick run through is for reference, and assumes you’ve got standard Android Developer SDK on your PC or Mac, and have enabled the Developer capabilities on your FireTV.
You’ll also need the Google Play Services (but not the store) which you’ll sideload, to get rid of some (but not all) annoying dialogs while using Screen. This YouTube video, which shows a similar process for Fire Phone (but over-complicates it significantly!) has a link to the necessary Google APKs.
Once you’ve got all the necessary bits, here are the adb commands (the order is important):
adb connect <IPAddressOfFireTV>
adb install <GoogleAccountManager>.apk
adb install <GooglePlayServices>.apk
adb install <GoogleServicesFramework>.apk
adb install <YahooScreen>.apk
On your FireTV, go to Settings > Applications > Manage Installed Applications.
Scroll until you find Screen, and launch it (it won’t show up in the normal FireTV App launcher — use Llama to fix that.)
Now that its launched, you have an input method problem. Yahoo Screen (as of this writing) was not made for TVs (or, apparently for Accessibility) so you have to connect a USB mouse to your FireTV (yes, it works just fine!) Alternatively, you can use adb to fake screen taps from the command line on your computer.
The mouse is easiest, but if you prefer the command line approach, this website has some good input instructions, but a quick example:
adb shell input touchscreen tap "200" "200"
This will tap the top left tile in the Yahoo Screen grid and start the video. Change the second number to “400” to get the next tile down, change the first number to “800” to get the next tile over, etc…
When you start a video, tou’ll get a warning about Google Play services not being supported, but you can use your FireTV remote to hit OK and the video will start. The back button on your FireTV remote will work, as will Home, but the video control buttons will not.
Hopefully Yahoo will update their app for other form factors and control mechanisms soon — when they do update the app, of course, you’ll have to re-install it.