[MTCD Android Head Units General] Kayhan 17#:
Dear xda-members,

this thread is about to describe the main steps for recovering your MTCD device for following symptoms:

the TFT stays black, no backlight working

no lights for the buttons

no sound from loudspeakers

no way to enter recovery, even with a prepared sdcard or certain button combinations

eject button for removing a disc in the drive does not affect anything

to sum up -> wholly dead device/brick after a failed dmcu.img flashing procedure

Thanks to a helpful user @Wadzio, i was able to recover my device and get it back to life.

For now the only downside is that I am not be able to flash the MCU via usual method through Recovery Menu from USB/SDCard.

Instead the dmcu.img needs to be converted to a dmcu.bin with the prepared bootloader which Wadzio developed and afterwards flashed with an UART/TTL device.

This is for now a very uncomfortable way but nonetheless we can save our devices from the bin :highfive:

My advice, don´t kill your device, but hey its easier said then done :eek:

To clarify up some things, I am in no way responsible for any damages that occur to your device using the guide provided here.

Every attempts are made on your own risk and responsibility, so take precautions.

Hardware you need:

PC, Notebook

USBtoUART Adapter, this is the one I am using USBtoUART 6-pin CP2102 Adapter

Soldering Iron

possibly a multimeter/voltmeter to measure the lines/connections

knife to remove the clear coat and apply solder wire to the lines/connections

thin wires, I prefer those for console modding back from the old days (kynar wire)

Software you need:

STM FlashLoader Demonstrator GUI

mtcdmcutool from Wadzio

Windows System in this Guide, alternatively you can use similar flashing tools with linux like dfu-util IIRC but not tested through me

MTCD Hardware preparations:

Disassemble your device and remove the px3/px5 board so you have a clear sight to the STM32 MCU, solder your wires as illustrated

View attachment 4421064

You need to solder six wires where

four

are connected to the UART-Adapter, take care to connect RxD from MCU to the TxD of the UART-Adapter and vice versa =>

MCU STM32 <=> UART-Adapter:

RxD <=> TxD​

TxD <=> RxD​

four wires are used to obtain the base connectivity(VDD 3.3v,VSS GND,TxD,RxD), the other two are just used to get the MCU into bootloader mode to gain access to it => this is done by shorting BOOT0 with VDD

Okay, here comes the actual guide :fingers-crossed:

connect the soldered wires to USBtoUART-Adapter

prepare recovery MCU binary file (.bin) with Wadzios tool(mtcdmcutool.exe) as it contains the bootloader!

mtcdmcutool.exe -r dmcu.img dmcu.bin

Plug in the USBtoUART-Adapter to the USB-Port(let it install drivers if not done already, note down or remember Serial-Port for next step)

start FlashLoader Demonstrator GUI and select the correct Serial-Port (f.e. COM3)

unplug USBtoUART-Adapter from USB-Port but don´t close FlashLoader Demonstrator GUI

now short BOOT0 to VDD to get MCU into the bootloader, dont disconnect the two wires yet

now plug in USBtoUART-Adapter back to USB-Port

Click next on the FlashLoader Demonstrator GUI, it will ask to remove Read/Write Protection, perform that and do a Global Erase in the next step

select the prepared recovery MCU file, set verify and starting address to 0x8000000

click next and the flash procedure begins, after flashing, remove connection between BOOT0 and VDD otherwise the Unit will not work

plug in MTCD in to Car or PC´s PSU and test

Remember, everytime you want to update your MCU, you need to do this procedure as for now the update routine is not implemented yet in the recovery DMCU file.

If there are any questions, don´t hesitate to ask ;):good:

I want to thank @Wadzio and @marchnz from here :highfive:

EDIT 20.02.2018:

Links to the initial thread and Wadzios guide

https://xdaforums.com/android-auto/...nt/bricked-px3-unit-how-to-save-unit-t3714667

https://xdaforums.com/android-auto/...uide-how-to-unlock-bricked-mcu-units-t3748646