Flashing OpenTX on a Flysky TH9X transmitter


After stumbling my way through flashing OpenTX on a stock Flysky TH-9X transmitter I thought I’d document the steps I took to create easy to follow instructions for anyone about to embark on the same journey.

I’m assuming you already know why you want to flash better firmware on your Flysky transmitter, and have basic soldering skills. If you don’t know why OpenTX is better, you can see some of the many improvements here. So lets get started!


 Software Side:

First things first. Download the latest version of the OpenTX Companion so we can download proper firmware as well as have the software required to perform the flash update. You can find the download here, just grab the latest version (currently 2.0.17). Once the download completes and the software installs/launches head to ‘settings -> settings’ and select “OpenTX for 9X board” from the radio type dropdown. Also check any build options you’ll be using, here’s what mine looks like:





Once complete, click ‘ok’ and then click the ‘download’ button from the top panel.



The download will complete and then ask if you want to flash your device now, select ‘no’ since we still have some soldering/hardware changes to make. Your software side is now good to go though!



 Hardware Side:

First lets open that controller up, unscrew the back as seen here:



After you open up the back, you’ll want to solder to the following pins using either a 6pin usbasp connector or in my case, breadboard jumper cables:



The result should look something like this (hopefully you do a cleaner job than I did:



Don’t forget you have to pre-tin the connection points and wires using flux and solder to get a solid connection.


After you finish soldering up the pins to their correct locations, connect the corresponding side to your usbasp like so:



Then connect it up to your laptop or PC



Hardware side complete, lets get the flash started!


Final flashing and cleanup:

Inside the OpenTX companion software (you still have that open, dont you?) first click on the small ‘gear and usb port’ button on the left and then in the ‘extra arguments’ field enter a -F . This will allow us to use quasi-fake usbasps, like most these days are. Make sure ‘usbasp’ is selected from the Programmer list as well:



Next click the ‘write firmware to radio’ button, again on the left (gear icon with red down arrow). Make sure everything except ‘use firmware start screen’ is UNchecked and then click ‘write to tx’.



After the flash process completes, unplug your usbasp from your PC and then power up your newly upgraded th-9x.



If you get the welcome splash and then the main menu, your all set! Time to close up the transmitter and screw everything back together. Also note, you can fit your ‘jumper’ cables for flashing through the battery compartment for future use, like so:









5 responses to “Flashing OpenTX on a Flysky TH9X transmitter”

  1. Mateen Baig Avatar
    Mateen Baig

    This was a really helpful post! Thanks a ton! Also, could you please tell me the list of mods you have done to your 9x?

    1. Michael Rickert Avatar
      Michael Rickert

      I don’t have a full list, but by far the two best improvements (besides flashing opentx) were:

      * Changing out the battery for a rechargable lipo battery (~$10)
      * Changing out the control sticks (gimbals) for taranis gimbals (~$30)

      Both can be done with little to no modifications to the actual 9x and they make a huge improvement when using the transmitter frequently.

  2. Bill McGann Avatar
    Bill McGann

    Thank you for this guide, it worked perfectly.
    In case anyone else is wondering about the difference in terminology between the picture of the PCB and the picture of the 10-pin plug: VTG = VCC, /RES = RST, and I connected GND to pin 10 only.

  3. James Avatar

    Hello Michael,
    If I need to change all the 2-pole switches to 3-poles or potentiometers and then use them to activate servos (-90, 0, +90), is that possible ? My FS-TH9X is being delivery as I post this.

    Many thanks.

  4. Michael Ross Avatar
    Michael Ross

    Mike , do I check the use profile start screen or use firmware start screen on write firmware to radio screen . Mike Ross

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