[Fire Q&A, Help & Troubleshooting] Robo-rooter:
SUCCESS! FLASHED NEXUS ROM ON FIRE 7 - 5.1.2 version!

I had bricked my Fire 7 a couple of times trying to install the Slim ROM with Flashfire.

I restored the stock 5.1.2 firmware by following Root Junky's video, "How to Firmware Restore or Unbrick your Amazon Fire 5th gen Tablet"

Finally the Nexus ROM install was a success.

I flashed the Nexus rom ("lp-fire-nexus-rom-ford-20160405.zip")

on to my Fire 7 (2015) firmware version 5.1.2 using Flashfire v.031.

I rooted the Fire 7 (firmware ver 5.1.2) with Root Junky's SuperTool ("AmazonFire5thGenSuperTool.zip" - April 6. 2016 version).

Here are the steps I used to root the Fire 7 and install the Nexus ROM on it.

I am going into detail in order to assist others.

Make sure your Fire 7 tablet is fully charged.

1. First I reset the Fire 7 to Amazon factory defaults. You do this by booting the Fire 7 while holding down the Power and Volume-Down (left side of Vol button) buttons. Don't release the buttons until the "Amazon system recovery" menu appears.

-While holding down the Power and Vol-Down buttons, first the "Amazon" logo appears, then the "Amazon system recovery" menu appears. Using the Volume keys, I highlighted "wipe data/factory reset" then I pressed the Power button to perform the task.

-Then using the Volume keys, I highlighted "wipe cache partition" and then I pressed the Power button to perform the task.

-Finally with "reboot system now" highlighted, I pressed the Power button to reboot the system.

2. The Fire logo appeared for a few minutes (a bar may appear and a message about updating software might appear). It may take up to 10 minutes to boot.

-Then the Fire 7 Setup screen finally appears. I selected the language and then I connected the Fire to my Wifi (Kingroot needs an internet connection in order to root the Fire using RootJunky's SuperTool). I skipped the portion of the Fire setup that registers the Fire with Amazon.

3. Go to SETTINGS, DEVICE OPTIONS on the Fire 7.

Tap on the SERIAL NUMBER field 7 to 10 times.

This opens a new field below titled, DEVELOPER OPTIONS. Click on Developer Options. Make sure ENABLE ADB is turned on (switch is to the right and orange color, rather than off and grayed out).

4. Using the data cable that comes with the Fire, I connected it to my Windows 10 computer on a USB 2.0 port. I copied the Nexus rom (lp-fire-nexus-rom-ford-20160405.zip) to the root folder of my SD Card.

5. I then rooted my Fire using RootJunky's SuperTool. There is thread about rooting the Fire 7 using Root Junky's Supertool here on xda forums. Make sure to watch Root Junky's YouTube video with great rooting instructions.

(AmazonFire5thGenSuperTool.zip - April 6. 2016 version).

6. I installed a copy of Fireflash v.031 on my Fire 7.

(RootJunky's SuperTool only had Fireflash v.030 at the time. I had a copy of Fireflash v.031 .apk that I downloaded from a European server. I replaced Root Junky's copy of v.30 with my copy of v.031 and installed Fireflash on my Fire 7 using Root Junky's SuperTool batch file). I then disconnected the data cable from the Fire 7.

7. I started Fireflash v.031 and made the following menu selections:

- Click the Red + and choose 'Wipe'

- Ensure System data, 3rd party apps and Dalvik cache are CHECKED

- Click the Red + button and choose 'Flash ZIP/OTA'

- Navigate to and choose the latest Fire Nexus ROM Zip (I used "lp-fire-nexus-rom-ford-20160405.zip" that I had previously loaded on the root folder of the SD Card.)

- Ensure Auto-mount and Mount /system read/write are UNCHECKED

- Move (drag) "Wipe" to the Top of the order (just above the ROM flashing).

- Press the big FLASH button.

- Ignore any warnings that appear.

8. The screen will go black for a few seconds.

-Then it will say, "Loading" and lines of text will go by rapidly for a few seconds.

-A red bar will then appear at the top of the screen titled "Fireflash".

-The rest of the screen is black. Don't touch the tablet. Just let the program run. It takes 5 or 10 minutes. It looks like nothing is happening, but it is.

-Finally the tablet will reboot. The Amazon logo will appear for a little while, then a pulsing color dots animation will appear. This dot animation will run for 5 or 10 minutes more as the tablet boots for the first time. Don't touch the tablet until a Setup screen appears.

9. You can now set up the tablet, registering it with Google and loading your desired apps.

Nexus is a nice ROM. Much better and faster than the stock Amazon Store ROM.

Good Luck with installing the Nexus ROM on your Fire 7, it's well worth all the effort.