Home > ARM, Контроллеры > Unbricking Xiaomi Yi action camera

Unbricking Xiaomi Yi action camera

Yi Action Camera

Yi Action Camera

Two days ago I received my Xiaomi Yi Action Camera bought on eBay. Official app told me that there were the new firmware for my cam. After update my camera become dead.

Camera now works like on this video:

First of all, I wrote a message to the Xiaomi. Well, answer confused me. “We can not help you because you got your camera not from the official seller”. Screenshot is provided below.

answer

answer

Polite version of GTFO. Just to be clear: I asked them for technical information, and not for refunds or replacement.

So I decided to teardown my camera. Main PCB with an Ambarella processor is shown below.

Main board

Main board

There are some pads in the upper left corner.

Pads

Pads

  • RX, TX — UART pins
  • VB, DM, DP, GND — USB pins
  • OUT — without an oscilloscope I can’t find what is this pin used for

First obvious step — connect USB UART converter (my converter is based on CP2102 chip). Result confused me: there were no output on pins, just +3.3V. I tried many configurations: with battery, without battery, with power connected directly to PCB pads. Nothing happens.

Second step: connect an USB connector to the VB, DM, DP, GND pads. Still no success. No response from the camera. Seems that all firmware is destroyed.


UPD 17.05.14
I’ve found 5 strange pads on the other side of the main PCB and I think that this is the JTAG interface:

jtag pins

JATG?

According to the JTAG specification, it uses 5 lines: TDI, TDO, TCK, TMS and TRST.

One can download Ambarella A7L product overview from the official website: . A7L SoC is based on the 600 MHz ARM 1136J-S core (ARM11 family, techincal reference on the ARM webiste).

I’ve bought Jlink debugger on Ebay. When I receive it, I’ll try to recognize if this pads are jtag pads. If it is successfull, I’ll try to flash a firmware suitable for a A7L chip (my camera is bricked anyway).

Stay tuned!

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  1. welcome.jn
    06.05.2015 at 01:23

    Do you have any luck with it after you wrote this? I have same problem…. Thnx for response…

  2. 17.05.2015 at 01:46

    Seems that it is dead completely…

  3. 21.01.2016 at 23:50

    Кирилл, помню оживлял регистраторы на Ambarella с помощью программы Direct USB. Для этого при подключении к USB зажимал одну из кнопок и появлялось новое устройство на компьютере. Но для прошивки нужен .elf файл, его нужно у производителя просить.

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