How to set custom Sleep or Screensaver times on the Amazon Fire TV or Stick without root

While the Amazon Fire TV and Fire TV Stick allow you to select from never, 5, 10, or 15 minutes for the screensaver timer, there is nowhere in the device’s settings to change the sleep timer. That’s set to 20 minutes regardless of how the screensaver is configured. Even though it’s not in the interface, it’s actually possible to set a custom sleep timer, a custom screensaver timer, or disable them altogether. This guide will show you how.
I’ve written guides about these topics in the past, but new methods have been discovered that do not require rooting the device.
The numeric values you use in this guide are in milliseconds. The default sleep value is 1200000, which is 20 minutes. The default screensaver value is 300000, which is 5 minutes. If you select “never” from the Fire TV’s screensaver settings, the screensaver timer gets set to 2147460000, which is about 24 days. Setting a value of 0 does not disable the screensaver but it does seem to work to disable the sleep timer, however it may be better to just use a very large value like Amazon does to disable the screensaver.
The sleep timer starts counting immediately after the device goes idle, not from when the screensaver starts. So setting a 5 minute screensaver timer and a 10 minute sleep timer will result in the device going to sleep 5 minutes after the screensaver starts.

Guide

1. Connect to your Fire TV device via ADB.
2. To set a custom sleep timer run the command:
   adb shell settings put secure sleep_timeout 123456789 
3. To set a custom screensaver timer run the command:
   adb shell settings put system screen_off_timeout 123456789
   (Remember to change 123456789 to the value in milliseconds that you want to set. Use 0 and 2147460000 to disable the sleep and screensaver timer, respectively.)
4. [OPTIONAL] To see the current timer value, and verify the value you entered was correctly saved, 
5. run this command for the sleep timer:
   adb shell settings get secure sleep_timeout
6. And this command for the screensaver timer:
   adb shell settings get system screen_off_timeout