DxO-One Preservation Project

Unofficial, collected information about the (discontinued) DxO-One Camera, a tiny camera with a 1" Sony Sensor and f/1.8 lens.

Contribution is very welcome!

Table of Contents

1. Software
   1. Ambarella RTOS
   2. Linux OS
   3. Firmware binary Analysis
2. Interesting things
   1. Connect DxO-One with Lightning Port to the Android App

More information is maintained in the wiki.

Software

The device is using Ambarella RTOS as its main OS for controlling the camera hardware and OLED display, and a separate Linux OS to control Wi-Fi functions. This is a quite popular chipset for (older) GoPro and other Action Camera clones as well as many Dashcams.

It seems that in case of the DxO-One, the Linux OS is mostly suspended and only woken up on-demand to connect to Wi-Fi. It might be interesting to achieve a shell to this OS, as it could allow adding wireless features (like FTP-transfer of images or 3rd party Wi-Fi control)

Ambarella OS has a own shell which can accept commands, but as the device is missing a UART-port I didn't find a way so far to connect to it (I suspect that it's possible to switch the USB-Port to UART, but I haven't found a method yet).

Ambarella RTOS

autoexec.ash:

On power-on (sliding the lens-cover open or connecting USB), the OS looks for the file autoexec.ash on the SD-Card and, if it exists, executes the shell-commands in it on the RTOS. This allows to do a few interesting things, such as enabling logging, switching USB-Modes, executing commands, etc.

Important

1. autoexec.ash needs to be stored at the root of the microSD-card (together with the DCIM-Folder)
2. Line-breaks need to be in Unix-format (LF, not CR LF)
3. Each command must be finished with a line-break, so the last line of the file should be empty.

To start investigating the Device, the first step is to re-route logging to a file stored on SD-card.

Log RTOS to SD-card

Download here: Log-to-SD

t dxo console 8
(empty)

When this file is saved on the root of the SD-card, on next power-on of the camera it will log its operation to the file console_debug.txt in the root of the microSD

Firmware binary Analysis

The mobile App contains the firmware binary to update devices with older versions.

• Latest version: 3.2.0
• Binary name: DXOSYS_3.2.0.ecef5ef809.BIN
• Path within iPhone app: /DxO ONE.app/Firmware

Unpacking the binary with gopro-fw-tools ( https://github.com/evilwombat/gopro-fw-tools ) reveals 6 files:

• section_0 - Ambarella RTOS
• section_1 - DSP Microcode
• section_2 - Ambarella ROMFS
• section_3 - Linux kernel
• section_4 - Linux Root FS
• section_5 - Firmware-Update OS

Interesting things

There's a Smartphone App accompanying the Device for iOS, and an Android-App for the (later) USB-C version of the camera.

Connect DxO-One with Lightning Port to the Android App

There is a way to connect the Apple-variant of DxO-ONE to the Android App (assumed here that the Android device has a USB-C port, but it would also work with micro-USB).

Possibly, this could work with a lightning port to USB-C adapter (not tested, happy to hear if someone tried it), but there is a way to do this via the microUSB port on the back of the device.

See here: Enable Lightning via microUSB, Disable Lightning via microUSB

Limitations:

1. Wi-Fi connection between Smartphone and DXO-ONE doesn't work (apparently some protocol-issue I didn't look into yet)
2. Not really convenient to use as viewfinder, but good to change settings on the camera (current app-setting is preserved by the camera and kept after disconnecting)