Amazon Fire 7 2019 (amazon-mustang)

Features
Flashing	Partial
USB Networking	Broken
Internal storage
SD card
Battery	Works
Screen	Works
Touchscreen	Works
Multimedia
3D Acceleration
Audio	Broken
Camera
Camera Flash
Connectivity
WiFi
Bluetooth	Broken
NFC
Miscellaneous
FDE
USB OTG	Partial
HDMI/DP
Sensors
Accelerometer
Magnetometer
Ambient Light
Proximity
Hall Effect
Haptics
Barometer

Amazon Fire 7 (2019)
	; Amazon Fire 7 showing the weston demo UI
Manufacturer	Amazon
Name	Fire 7 (2019)
Codename	amazon-mustang
Released	2019
Type	tablet
Hardware
Chipset	MediaTek MT8163V/B (64-bit quad-core)
CPU	4x 1.3 GHz Cortex-A53
GPU	Mali-T720 MP2
Display	600x1024 IPS
Storage	16 GB
Memory	1 GB
Architecture	armv7
Software
Original software	Android (Fire OS)
Original version	7.1.1 (Fire OS 6)
postmarketOS
Category	testing
Pre-built images	no
postmarketOS kernel	4.9.77

Contributors

NoriTech

Maintainer

NoriTech

Users owning this device

BlackEyedSquid (Notes: 16GB, amonet exploit)
NoriTech (Notes: ported)
ThatGeekZen

How to unlock bootloader

The bootloader can now be through a hardware method: https://forum.xda-developers.com/amazon-fire/orig-development/fire-7-2019-mustang-unbrick-downgrade-t3944365

How to enter flash mode

Press and hold Power + Volume Up

Installation

Due to the fact that fastboot doesn't work even after using the amonet exploit, you will need to export the boot image and flash it with twrp. Then flash this dummy zip which will force twrp to reapply the amonet exploit.

Another option is exporting a flashable zip that can be flashed using twrp. Refer to Installation Guide for postmarketOS

Amonet

Amonet is an lk exploit used to boot an unsigned kernel. Sources of amonet are available here: https://github.com/xyzz/amonet/tree/mustang. This exploit is installed by a bootrom exploit. But probably some 2nd stage bootloader is a good idea.

Mainlining

There is some work on mt8163 mainline, for amazon-karnak, but it will be easy to get it on mustang. For now serial console and simplefb is working. Pwrap and pmic seems to be working. https://github.com/mt8163-mainline/linux

Device problems

Mainline is not yet usable.
Panfrost (driver for mali-t720) is wip, and not avalible in downstream (Merged in linux 5.2)
This device use exploit due to locked bootloader. See #Amonet.
This device's bl is not very good for running linux, due to it appends much of bad cmdline params, and some things in device tree.

Useful information

Serial/UART

921600 baud 8N1
RX & TX pads are on the back of the board clearly marked. A cheap RS232-to-USB will work.

Please approach with caution since the display flex cable (top center) is glued onto the board but the board can be flipped over while it is connnected.