User manual


AIO-3399JD4 standard set includes the following accessories:

  • AIO-3399JD4 main board ×1

  • brass antenna ×1

  • 12V-2A Power adapter ×1

  • Dual male usb data cable ×1

Other optional accessories :

  • Firefly Serial Module

In addition, you may need the following accessories during use:

  • Display device

    • Monitor or TV with HDMI interface and HDMI cable

  • Network

    • 100M/1000M Ethernet cable, and wired router

    • WiFi router

  • Input devices

    • USB wireless/wired mouse/keyboard

    • infrared remote control (need to connect to the infrared receiver)

  • firmware upgrade and debugging

    • Dual male usb data cable

    • serial port to USB adapter.

Firmware type

Firmware comes in two formats:

  • Original firmware(raw firmware)

  • RK firmware(Rockchip firmware)

    Original firmware is a firmware that can be upgraded to a storage device in a bit-by-bit replication mode. It is the original image of the storage device. Raw firmware is generally upgraded to an SD card, but it can also be upgraded to an eMMC. There are many tools available to upgrade the original firmware:

    RK firmware is a firmware packaged in Rockchip proprietary format and upgraded to eMMC flash memory using upgrade_tool(Linux) or AndroidTool(Windows) tools provided by Rockchip. RK firmware is Rockchip’s traditional firmware packaging format and is often used on Android devices. In addition, Android’s RK Firmware can be upgraded to an SD card using the SD Firmware Tool.

    Partition image is the image data of a partition and is used to store the upgrade of the corresponding partition of the device. For example, the compilation of the Android SDK will construct boot.img, kernel.img and system.img etc. Partition image file ,the kernel.img will be written in eMMC or SD card “the kernel” partition.

Download and update firmware

The following is a list of supported systems:

  • Android 7.1

  • Ubuntu 16.04

  • Ubuntu 18.04

  • Debian 9

Choose the right tool to upgrade the firmware according to the operating system used:

  • upgrade to SD

    • Graphical interface upgrade tool:

    • Command line upgrade tool:

      • dd (Linux)

  • upgrade to eMMC


After confirming the correct connection of motherboard accessories, insert the power adapter into a live socket and the power line interface into the development board. The development board will automatically start up after the first power on. After the shutdown of the Android system is selected, the power supply of the development board is maintained. At this time, AIO-3399JD4 is as follows:

  • Long press the power button for 3 seconds (extension button)

When the machine is turned on, the blue power indicator light will be on. If the board is connected to the HDMI monitor, you can see the official logo of Firefly.

Serial debuge

Purchase the adapter

There are many USB adapter to serial port on the shop, divided by chip, there are the following:

Note: the default baud rate of RK3399 is 1500000, some USB to serial chip baud rate can not reach 1500000, the same chip may have different series, so be sure to confirm whether to support before purchasing.

Hardware connection

Serial port to USB adapter, there are four cable:

  • 3.3v power supply, no connection required

  • GND, ground wire for serial port, GND needle for serial port of development board

  • TXD, output line of serial port, TX needle of serial port of development board

  • RXD, input line of serial port, RX needle of serial port of development board

Note: if you encounter problems that TX and RX cannot input and output when using other serial port adapters, you can try to adjust the connection between TX and RX.

AIO-3399JD4 Serial port connection diagram:


Connection parameters

AIO-3399JD4 uses the following serial port parameters:

  • Baud rate: 1500000

  • Data bit: 8

  • Stop bit: 1

  • Parity check: none

  • Flow control: none

Use serial debuge on Windows

Install the driver

Download driver and install:

If you can’t use PL2303 normally on Win8, use or older version of the old driver, please refer to This article.

If you install the CP210X driver from the official website on the Windows system, you can set the serial port baud rate to 1500000 using tools such as PUTTY or SecureCRT. If you cannot set the baud rate or it is invalid, you can download the old version driver.

After the adapter is inserted, the system will prompt for the discovery of new hardware and initialization, and then the corresponding COM port can be found in the device manager:


Install software

Putty or SecureCRT are commonly used for Windows. Putty is open source software and SecureCRT is used in a similar way. Here to Download putty(Recommended download putty.zip, it contains other useful tools.)

Extract and run PUTTY.exe.

  • Select “Connection type” to “Serial”.

  • Modify “Serial line” to the COM port found in the device manager.

  • Set “Speed” to 1500000.

  • Click “Open” button.


Use serial debuge on Ubuntu

There are many options available on Ubuntu:

  • minicom

Here’s how minicom works.


sudo apt-get install minicom

To connect the serial port line, see what the serial port device file is. The following example is /dev/ttyusb0

$ ls /dev/ttyUSB*


$ sudo minicom
Welcome to minicom 2.7                                       
OPTIONS: I18n       
Compiled on Jan  1 2014, 17:13:19.     
Port /dev/ttyUSB0, 15:57:00                                 
Press CTRL-A Z for help on special keys

Based on the above tips:Press Ctrl-a and then press Z again to bring up the Help menu.

                          Minicom Command Summary                      |
  |                                                                    |
  |              Commands can be called by CTRL-A <key>                |
  |                                                                    |
  |               Main Functions                  Other Functions      |
  |                                                                    |
  | Dialing directory..D  run script (Go)....G | Clear Screen.......C  |
  | Send files.........S  Receive files......R | cOnfigure Minicom..O  |
  | comm Parameters....P  Add linefeed.......A | Suspend minicom....J  |
  | Capture on/off.....L  Hangup.............H | eXit and reset.....X  |
  | send break.........F  initialize Modem...M | Quit with no reset.Q  |
  | Terminal settings..T  run Kermit.........K | Cursor key mode....I  |
  | lineWrap on/off....W  local Echo on/off..E | Help screen........Z  |
  | Paste file.........Y  Timestamp toggle...N | scroll Back........B  |
  | Add Carriage Ret...U                                               |
  |                                                                    |
  |             Select function or press Enter for none.               |

Press O to enter the setting interface, as follows:

           | Filenames and paths      |   
           | File transfer protocols  |   
           | Serial port setup        |  
           | Modem and dialing        |  
           | Screen and keyboard      | 
           | Save setup as dfl        | 
           | Save setup as..          |                 
           | Exit                     |                 

Move the cursor to Serial port setup, press enter to enter the Serial port setup interface, then enter the letter prompted earlier, select the corresponding option, and set it as follows:

   | A -    Serial Device      : /dev/ttyUSB0                              |                                          
   | B - Lockfile Location     : /var/lock                                 |                                          
   | C -   Callin Program      :                                           |                                          
   | D -  Callout Program      :                                           |                                          
   | E -    Bps/Par/Bits       : 1500000 8N1                               |                                          
   | F - Hardware Flow Control : No                                        |                                          
   | G - Software Flow Control : No                                        |                                          
   |                                                                       |                                          
   |    Change which setting?                                              |                                          
  • Note: Hardware Flow Control and Software Flow Control should be set to No, otherwise it may be impossible to input.

Go back to the previous menu and select Save setup as DFL to Save as the default configuration, which will be used by default later.