[Fire HD 8 and HD 10 Original Android Development] pascal009:
Stuck at Preloader. Seeking help.

Fire HD 10 7th Gen (suez), Fire OS Fire OS 5.6.8.0.

Step 1 ran successfully. Because of the firmware version it suggested bricking the device to which I entered YES.

I have stopped and disabled ModemManager.

I disconnected the device ran bootrom-step-minimal.sh. At the "Waiting for bootrom" prompt I connected the device and the script starting doing its thing. It finished with a message "reboot into 'hacked fastboot' mode".

I rebooted the device - it went into a boot loop with the white Amazon logo. I tried rebooting it a few times but it still went

into a boot loop.

At this point I followed the OP to unbricking the device per the guide by @retyre

https://xdaforums.com/t/unlock-root-twrp-unbrick-fire-hd-10-2017-suez.3913639/

I disassembled the device, unplugged the LCD and unscrewed the PCB. I grounded the point per the diagram, plugged the USB cable into the Ubuntu box. Then I started "sudo ./bootrom-step.sh" and at the prompt removed the short and hit enter. This worked on the third attempt.

The script finished with a message to reboot into "hacked fastboot" mode. Out of curiosity I ran "adb devices", the output was

GXXXXXXXX recovery.

I rebooted device but the screen remained black. Upon close inspection I noticed that I didn't press flat the tiny clamp fixing the LCD cable in its socket. I fixed it and tried to turn it on again. Device emitted a weak "ding" but nothing else.

The output of lsusb is as follows:

~/Downloads/FireHD9/amonet-suez/amonet$ lsusb

Bus 001 Device 044: ID 0e8d:2000 MediaTek Inc. MT65xx Preloader

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Bus 002 Device 002: ID 045e:0084 Microsoft Corp. Basic Optical Mouse

Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

The output of dmesg is as follows:

[ 551.724195] usb 1-1: new high-speed USB device number 35 using ehci-pci

[ 551.883109] usb 1-1: New USB device found, idVendor=0e8d, idProduct=2000, bcdDevice= 1.00

[ 551.883164] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0

[ 551.883186] usb 1-1: Product: MT65xx Preloader

[ 551.883200] usb 1-1: Manufacturer: MediaTek

I tried to run bootrom-step.sh and got the following error message:

~/Downloads/FireHD9/amonet-suez/amonet$ sudo ./bootrom-step.sh

[2022-04-26 00:08:46.311111] Waiting for bootrom

[2022-04-26 00:09:51.437565] Found port = /dev/ttyACM0

[2022-04-26 00:09:51.466105] Handshake

[2022-04-26 00:09:51.488426] Disable watchdog

b''

b'\x00\x01'

Traceback (most recent call last):

File "main.py", line 192, in <module>

main()

File "main.py", line 82, in main

handshake(dev)

File "/home/bigbang/Downloads/FireHD9/amonet-suez/amonet/modules/handshake.py", line 11, in handshake

dev.write32(0x10007000, 0x22000000)

File "/home/bigbang/Downloads/FireHD9/amonet-suez/amonet/modules/common.py", line 163, in write32

self.check(self.dev.read(2), b'\x00\x01') # arg check

File "/home/bigbang/Downloads/FireHD9/amonet-suez/amonet/modules/common.py", line 90, in check

raise RuntimeError("ERROR: Serial protocol mismatch")

RuntimeError: ERROR: Serial protocol mismatch

~/Downloads/FireHD9/amonet-suez/amonet$

I tried to run bootrom-step-minimal.sh and got the following error message:

~/Downloads/FireHD9/amonet-suez/amonet$ sudo ./bootrom-step-minimal.sh

[2022-04-26 00:04:58.659839] Waiting for bootrom

[2022-04-26 00:05:15.785442] Found port = /dev/ttyACM0

[2022-04-26 00:05:15.813667] Handshake

[2022-04-26 00:05:15.835803] Disable watchdog

b''

b'\x00\x01'

Traceback (most recent call last):

File "main.py", line 192, in <module>

main()

File "main.py", line 82, in main

handshake(dev)

File "/home/bigbang/Downloads/FireHD9/amonet-suez/amonet/modules/handshake.py", line 11, in handshake

dev.write32(0x10007000, 0x22000000)

File "/home/bigbang/Downloads/FireHD9/amonet-suez/amonet/modules/common.py", line 163, in write32

self.check(self.dev.read(2), b'\x00\x01') # arg check

File "/home/bigbang/Downloads/FireHD9/amonet-suez/amonet/modules/common.py", line 90, in check

raise RuntimeError("ERROR: Serial protocol mismatch")

RuntimeError: ERROR: Serial protocol mismatch

~/Downloads/FireHD9/amonet-suez/amonet$

This is where I am now. Device does not power on, the screen is black.

I would appreciate any help!