If you’ve managed to brick your Fire TV or for whatever reason are unable to get to the settings menu to perform a factory reset, here is how to enter recovery mode without fully booting into the Fire TV’s operating system.
To do this you will need a USB keyboard with a “Print Screen” or “SysRq” key. Mac keyboards generally do not have this key so will not work. Before you get started, plug the USB keyboard into the Fire TV and unplug the Fire TV’s power. Now plug the power in and while the Fire TV is booting, you need to press the following 3 keys simultaneously: Alt + Print Screen + i
Pressing those 3 keys sends a “kill all tasks” command to the Fire TV. If you kill all tasks during boot up enough times, the Fire TV will enter Androids default Recovery Mode. So after pressing Alt + Print Screen + i, the Fire TV will flicker and restart the boot up process. While it’s trying to boot up the second time, press Alt + Print Screen + i again. A good time to press it is as soon as you see the colorful Fire TV logo. Repeat this process several times, pressing Alt + Print Screen + i during boot, until the Fire TV displays the message “The System Update was not successful.” When you see this message, you are now in Recovery Mode. Note that depending on your TV, the colorful Fire TV logo may appear off screen, so you’ll need to guess when it appears.
Once on the “Update was not successful” screen, press the Home key on your keyboard. This should bring up a menu in the upper left corner. If a menu doesn’t appear, press Alt + Print Screen + i one more time. The screen will go black and then return to the “System Update was not successful” screen. Pressing the Home key should now definitely bring up the menu. Once you see the menu, use the arrow keys on the keyboard to highlight the factory reset option and hit enter.