Amazon Fire TV Cube supports Safe Mode, Shutdown, Fastboot, and ADB over USB

I spent some time poking and prodding the Amazon Fire TV Cube today and discovered a few undocumented capabilities that I figured I’d share. None of the things I found are terribly exciting or lead to anything significant at this point, but they may interest those of you who might like to tinker with the underlying Android roots of the Fire TV Cube.

Safe Mode

Surprisingly, the Fire TV Cube supports Safe Mode. As far as I’m aware, it’s the first Fire TV model to do so, or at least the first one to have an easy way to enable the mode. Safe Mode is a system state that prevents any 3rd-party apps from launching. It’s a feature of Android that is meant to help users diagnose and fix issues that are caused by 3rd-party apps. For example, if a buggy/defective app that you installed keeps causing the device to crash or reboot, Safe Mode gives you a way to boot the device without letting the app run, so that you can uninstall it.

To boot into Safe Mode on the Fire TV Cube, disconnect the power cable, press and hold the Volume Down button on the top of the Fire TV Cube, and connect the power cable. Keep holding the Volume Down button until you see “Safe Mode” appear in the lower left corner. It should appear just after the “Fire TV” boot animation disappears. To exit Safe Mode, simply restart the Fire TV Cube by going to Settings > Device > Restart

While in Safe Mode, no 3rd-party apps will be able to launch. Only system apps that came installed on your Fire TV Cube from the factory can be launched. You can stream videos from Amazon while in Safe Mode, but not from any other streaming service or app.

Shutdown

I’m not entirely sure what this next capability is for or what it does exactly, so for now, I’m just going to call it “Shutdown” because that’s the best way to describe it. If anyone knows more about this, please comment below or email me.

While the Fire TV Cube is on, if you hold the action (dot) button on the top of the device for 15 seconds, the Fire TV Cube goes into a sort-of Shutdown state. The screen goes black and all activity, including ADB logcat, seems to stop. However, the device is still powered on to some extent because the mute button remains red if the mics are muted, and you can still toggle mute on and off. The device also continues to register on the USB bus if it is connected to a PC via a USB cable. In every other sense, it seems to act as if it has shutdown. Pressing the action button while in this state causes it to reboot.

Fastboot

The Fire TV Cube, like all other Fire TV models before it, supports Fastboot. This is an Android state/tool that lets you modify the device’s operating system if you have the correct privileges. As with all other Fire TVs, the Fire TV Cube comes with a locked bootloader that prevents you from using fastboot to modify the device.

I expected to find a button combination to hold that would cause the Fire TV Cube to enter Fastboot mode or Recovery mode, but nothing I tried worked. This was a bit surprising, since the Echo Show supports Fastboot/Recovery by holding the Mute and Volume Down button during boot. holding the same buttons on the Fire TV Cube just caused it to boot into Safe Mode. The only way I was able to enter Fastboot mode was to connect via ADB and run the command adb reboot bootloader while connected to a computer via the micro USB port.

ADB over USB

All Fire TV models support ADB connections over WiFi, but only the Fire TV 1 and Fire TV 2 officially support ADB over a USB connection. Even though it doesn’t officially support it, it is possible to make an ADB over USB connection to the Fire TV Cube. To do so, you need to enable ADB under the developer options, connect the Fire TV Cube to a computer using the Cube’s micro USB port, and then reboot the Cube. When it boots up, you’ll find that an ADB over USB connection has been established. Windows users may need to install USB drivers for this to work. Functionaly, ADB over USB seems to be identical to ADB over WiFi.

Recovery

Lastly, if you connect to the Fire TV Cube via ADB and run the command adb reboot recovery it will reboot into what appears to be its default recovery mode. A line drawing of a Fire TV Cube will appear on the screen with the text “No Command” written underneath. All Fire TVs use their default recovery mode to install software updates and to perform a factory reset when the option is selected by the user from the Settings > Device menu. The “No Command” text is likely displayed because Recovery mode was entered even though the Fire TV Cube did not have an update to isntall nor was it instructioned to execute a factory reset, which are normally the only reasons for it to boot into recovery mode. Unfortunately, I could not find any options or actions available while in recovery mode, like have been available on some earlier Fire TV models.

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7 comments
  1. tech3475 says:

    Not sure if you’ve tried this, but in the past when I’ve encountered “No Command” in recovery, trying different combinations of the volume/power buttons usually bought up the traditional recovery menu.

  2. AllanUSC says:

    I have been trying to connect the new Cube to my Yamaha receiver via Bluetooth, the same way I had an Echo Dot connected, and the Cube can’t seem to see the receiver.

    Has anyone tried to connect the Cube to a receiver via Bluetooth? Is there a reason it doesn’t work?

    I’d like to make this work so that I can play music from the Cube without turning on the TV.

    • Don Black says:

      I connected mine to Polk audio via Bluetooth, it should have asked that in the beginning of setup. Use the setup wizard and follow the directions it was really simple. Keep in mind you must have both remote controls while trying to achieve the pairing.

  3. Frank says:

    Hey has anyone had their cubes act janky. It’s the only word that I can describe it’s weird behavior., she’s not as responsive as my other Amazon devices also since I’ve installed it into my network my Sonos ones don’t really play nice with her contemplating changing the Wake word. I find I have to scream to get her to wake up and or respond and the response time from when I issue a command to coming back out I find to be very slower then my other devices. Not really impressed with it over my Fire TV 3 and Logitech Harmony found they work better than this Amazon pure device

    • Eric says:

      Mine is janky. After running for a few days, it gets very sluggish. Even mp3 files will not play properly in Plex until I reboot.

  4. I don’t know what people are experiencing but mine are great. It’s unfortunate how some don’t work I get quality tho trust me.

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