A Fire TV stick doesn't have a kiosk mode of its own, but a kiosk browser app gives it one: it opens a single web page full screen and keeps it there. DisplayValet uses Fully Kiosk Browser for this.
Set up the kiosk
- Unlock Developer Options: Settings → My Fire TV → About → select the device name 7 times.
- In Developer Options, allow installing unknown apps for the Downloader app.
- Install Downloader from the Appstore, then use it to install Fully Kiosk Browser from fully-kiosk.com.
- In Fully Kiosk's settings, set the Start URL to the display's address from DisplayValet, and turn on Keep Screen On and Autoplay Videos.
- Set the Fire TV's own screensaver to Never (Settings → Display & Sounds → Screensaver).
Let DisplayValet look after it (optional)
- Turn on ADB debugging in Developer Options, press Connect on the display's card in DisplayValet, and choose Always allow on the TV.
- DisplayValet can then put the Fire TV to sleep and wake it on a schedule, and reopen the kiosk if someone switches to another app or the Fire TV restarts.
- TVs with Fire TV built in turn fully off and on this way. With a stick in an older TV, the TV itself may not follow; use the TV's own timer for that.
Tested on the Fire TV Stick (AFTKM) and a Fire TV 4-Series TV.