[Fire General] _SWaTcH_:
First i want to say Speacial Thanks to [MENTION=9667509]xyz`[/MENTION], [MENTION=7104332]k4y0z[/MENTION], [MENTION=8132642]diplomatic[/MENTION] and [MENTION=5749760]ggow[/MENTION] who make it possible to get a costum rom on a fire 7(9th gen)!

But i needed informations from more sites to get it work and i want to collect all informations in this Thread to make it easier for noobs like me :D I hope thats okay, i only collect informations, credits goes to:

[MENTION=7104332]k4y0z[/MENTION] and [MENTION=9667509]xyz`[/MENTION] for the bootloader hack

[MENTION=8132642]diplomatic[/MENTION] for the temp root

[MENTION=5749760]ggow[/MENTION] for the lineageos for mustang

So i will show the hole way From Stock FireOs 6.3.1.2 until you boot LineageOs 14.1

In this Guide i will use the Software method to get into bootrom mode. Software method: use mtk-su to do the thing.

Careful: this will break your device… and then you fix it by installing a new OS.

Any OS above 6.3.1.2 needs to use the hardware method!

Here you can find the hardware method: https://xdaforums.com/amazon-fire/orig-development/fire-7-2019-mustang-unbrick-downgrade-t3944365

I flash some devices but that was the most difficult. It will help if you have some experience how to flash devices.

Make sure you read this guide completely before starting!

This Hardware you need:

Working Amazon Fire 7 2019 9th gen (tested with FireOs 6.3.1.2)

USB cable for Kindle Fire

empty USB drive (min. 2Gb)

computer that can boot from USB drive

Download This Software:

lubuntu-19.10-desktop-amd64.iso # get it here https://lubuntu.net and download the AMD64 version

rufus-3.9.exe # get it here https://rufus.ie

mtk-su_r21.zip # get it here https://xdaforums.com/attachment.php?attachmentid=4971443

amonet-mustang.zip # get it here https://xdaforums.com/attachment.php?attachmentid=4785431&d=1561925516

lineage-14.1-20190827-UNOFFICIAL-mustang.zip # get it here https://androidfilehost.com/?w=files&flid=297948

open_gapps-arm-7.1-mini-20200403.zip # go to https://opengapps.org and choose AMR -> 7.1 -> and a variant of your choice i use mini

Step 1 Prepare Usb Stick

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Okay first we make the usb stick ready with Lubuntu.

1.1 Start the rufus-3.9.exe

1.2 choose the Lubuntu image file and push start

1.3 it will ask ISO image mode or DD image mode, choose the DD image mode!

1.4 after that put these files to C:\ :

mtk-su_r21.zip

amonet-mustang.zip

lineage-14.1-20190827-UNOFFICIAL-mustang.zip

open_gapps-arm-7.1-mini-20200403.zip

1.5 Turn off your Computer!

Step 2 Boot Live Linux

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2.1 Turn on your Computer and boot from usb and start lubuntu

(2.1.1 If you use wlan connect with it)

2.2 Open a terminal window # (go to "start button" at the left corner choose -> system tools -> QTerminal)

2.3 type "sudo apt install python3 python3-serial android-tools-adb android-tools-fastboot" push enter

2.3.1 it ask you something, say yes

2.4 type "sudo apt-get remove modemmanager" push enter

2.4.1 it ask you something, say yes, if it done close this window

2.5 Click on the "Computer" icon on Desktop

2.6 Search your Windows device and copy the 4 files from step 1.4 to lubuntu home directory (make it easier later)

Step 3 Prepare kindle

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3.1 Go to settings and enable developer options (need to push the serialnummber multiple times)

3.2 Go to developer options Enable USB debugging

3.3 Connect kindle to computer

3.3.1 On the kindle,

3.3.2 pull down the menu,

3.3.3 click the USB charging, “tap for other USB options” and select PTP for “transfer photos”

3.3.4 Click Accept to allow permission for your computer.

Step 4 Temporary root (Terminal window1)

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4.1 Open the mtk-su_r21.zip

4.2 copy the arm folder to lubuntu home directory

4.3 Open a new terminal window

4.4 type "sudo adb push arm/mtk-su /data/local/tmp” push enter

once successful, run these commands:

4.5 type "adb shell" push enter

4.6 type "cd /data/local/tmp" push enter

4.7 type "./mtk-su" push enter

4.8 type "getenforce" push enter # Just to confirm it says Permissive

4.9 type "echo 0 > /sys/block/mmcblk0boot0/force_ro" push enter

4.10 type "dd if=/dev/zero of=/dev/block/mmcblk0boot0 bs=512 count=8" push enter

Dont close this window!. you will need it in a moment.

Step 5 Bootrom Mode (Terminal window2)

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5.1 Open the amonet-mustang.zip

5.2 copy the amonet-mustang folder to lubuntu home directory

5.3 Open a new terminal window

5.4 type "cd amonet-mustang/" push enter

5.5 type "sudo ./bootrom-step.sh" push enter

5.6 Go back to the first Terminal window and type "reboot" push enter

5.7 Go back to the second Terminal, the tablet should restart, and the amonet script will begin to run.

Press Enter to continue, it will start copying things. Should take about 4 minutes.

Once the script finished, the kindle will restart into fastboot mode.

5.8 All you will see if the amazon logo. to verify that the device is in fastboot mode go back to the first Terminal window

and type "sudo fastboot devices" push enter

it will list the device # if it find 1 device you make all right

Step 6 Fastboot & TWRP

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6.1 Go back to the second Terminal window

6.2 type "sudo ./fastboot_step.sh"

The tablet will flash some text and do a few things. give it a minute or two.

The tablet will flash and appear to restart, let it do its thing until the screen goes dark.

6.3 Tap the power button twice and TWRP will pop up.

SUCCESS! # TWRP (Team Win Recovery Project) is now installed and can be launched by holding down VOL Down (left most button from pwr) and Power when starting up the device.

(At this point you can try to put the files on a SD Card, but i try it with multiple ones and TWRP dont find one, if you have one that work you can jump to step 8.4)

Edit: or use adblink from here https://xdaforums.com/fire-tv/themes-apps/adblink-v2-04-t3389826

Step 7 Set permissions to Copy

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7.1 In TWRP on you kindle push wipe -> push Format Data and Swipe to reset

7.2 Now we need to obtain the idVendor of the kindle.

Go to the first Terminal window and type "sudo dmesg" push enter look for idVendor"XXXX", for me, the ID was "18d1".

7.3 Next, you need to give the ”plugdev” group access to the device.

You are going to create a file and then change some permissions then restart the services.

7.4 type "sudo nano /etc/udev/rules.d/51-android.rules" # create the file

7.5 and type the following line: #(Change idVendor to your ID)

SUBSYSTEM=="usb", ATTR{idVendor}=="18d1", MODE="0666", GROUP="plugdev"

7.6 push ctrl + x , and hit y to save. # push a button and it close but hold the terminal open

7.7 Now assign read permissions on the files, reload udev and reload the adb daemon:

7.7.1 type "sudo chmod a+r /etc/udev/rules.d/51-android.rules" push enter

7.7.2 type "sudo udevadm control --reload-rules" push enter

7.7.3 type "adb kill-server" push enter

7.7.4 type "adb start-server" push enter

(You may have to disconnect and connect again your device to the USB port) # i dont needed it

Step 8 Copy & Install LineageOs

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NOW you can copy the files using the adb push command, like we did before.

8.1 type "sudo adb push /lineage-14.1-20190827-UNOFFICIAL-mustang.zip /data/local/tmp/lineage.zip" push enter

8.2 type "sudo adb push /open_gapps-arm-7.1-mini-20200403.zip /data/local/tmp/gapps.zip" push enter

After it finish copying, use TWRP to install the image

8.3 In TWRP push install go to path /data/local/tmp/ # there you find lineage.zip & gapps.zip

8.4 Choose lineage.zip and swipe to install

8.5 After that go back and choose gapps.zip and swipe to install

8.6 if its done you can push "Reboot System"

You are Finaly Done LineageOs 14.1 will booting now! # it will take some time at the first boot

Edit:

Install the "sod-fix-test.zip" by using TWRP you can find it here https://xdaforums.com/showpost.php?p=80621157&postcount=253 [MENTION=9906981]Ziona[/MENTION]

(This fix the charge issue)

i find so much usefull things at xda-developers to flashing much devices include this device :D

So for this device it was really difficult and i was think it will be great thanks when i collect all informations for other(and me for the next time :P).

And i think, thats understandable for anyone. I Hope it will help other People too.

Sources:

Unlock & root By xyz` https://xdaforums.com/amazon-fire/orig-development/fire-7-2019-mustang-unbrick-downgrade-t3944365

Amazing Temp Root By diplomatic https://xdaforums.com/android/development/amazing-temp-root-mediatek-armv8-t3922213

LineageOS 14.1 By ggow https://xdaforums.com/amazon-fire/orig-development/rom-lineage-14-1-t3957329