Working With OpenTX Companion


OK, you’ve made sure that you have a valid STM 32 BOOTLOADER installed. Now it’s time to download your very own copy of OpenTX2.x and OpenTX Companion2.x and update your firmware. Like many things in life, the first time you do this it can be, well, interesting. If you’ve accomplished what was required in the previous lesson, Using Zadig, things should proceed smoothly.

Vitally Important Note:

If you've been using Companion 9X and an earlier version of OpenTX, you already have a working STM BOOTLOADER installed, and you can update to v2.x directly through your working copy of Companion 9X. When Companion 9X informs you of a newer version being available and asks you if you'd like to download that version, select, "Yes", and follow the prompts to a successful upgrade. Just be certain that you've got current backups of both your existing firmware (r2490?) and your EEPE file in case something goes wrong.

On the other hand, if you have a working copy of Companion 9X, you’ve probably already done that! If you have not, and would like some guidance along the way, see Part 1: Downloading and Installing OpenTX Companion for some guidance.

Lesson Goals

This lesson sets up the next two lessons where you’ll download both OpenTX Companion and OpenTX, then install OpenTX Companion on your computer and flash the firmware to your transmitter. When you’re done, you’ll be a full fledged member of the OpenTX family!


  • An understanding of how to access and download files from a Web page
  • Know where the downloaded files will be stored
  • How to install applications on your computer


Traditionally, this has been one of the more frustrating aspects of OpenTX. It’s difficult to embrace the firmware if you can’t even get it on your transmitter! Much of the frustration was because Windows wouldn’t automatically install the correct driver (STM 32 BOOTLOADER), and some of us-myself included-very quickly became lost and hit the proverbial wall. If you’ve completed the two Zadig lessons, you should have that problem solved. However, installing the correct driver is only the first of two steps involved in upgrading your firmware. Downloading and actually flashing the firmware is the second step.


At this time, there is only one way that I know of to flash OpenTX v2.x firmware to the Taranis the first time, and that's to use Companion (either 9X or OpenTX Companion) with the transmitter OFF. After the first install there are three different methods you can use. These are detailed in the discussion notes.

Lesson Progression

  1. Download and at least glance through the Discussion Notes.
  2. If you haven’t already watched them two or three times, watch Scott Page’s video: Upgrading to v2.0.
  3. Read the discussion notes BEFORE installing OpenTX Companion.
  4. Using the checklist from the “Using Zadig” lesson (up next) as a guide, connect your Taranis to your computer with the TX OFF.
  5. Open the Device Driver and confirm that the STM 32 BOOTLOADER is loaded. You’ve done this two or three times before.  Please, PLEASE take the time to do this step. If the bootloader isn’t working, you won’t be able to flash the firmware.
  6. Follow the steps in the Discussion Notes to install OpenTX Companion and flash the latest version of OpenTX firmware. The lasted version of OpenTX Companion is HERE.
  7. As part of the install, OpenTX Companion may tell you that a newer version of OpenTX exists. This is the easiest way to get the new firmware. If so, accept the offer and continue. Follow the prompts in OpenTX Companion to complete flashing the firmware. After this, OpenTX Companion will automatically inform you of any updates.
  8. You’ll be tempted to engage the circuit activator/de-activator analog interrupter/circuit completion device (aka: turn on the switch) on the Taranis before you finish reading the discussion notes. Save yourself some serious heart palpitations by finishing reading the notes before you turn on your transmitter.


OpenTX Companion — 6 Comments

  1. I do not know if this is the correct place to ask a question,but here goes.I have the Companion 9x on my computer and had the current model memories on my PC.I downloaded the latest Open TX Companion,programmed a new model on the PC using the Open TX program.I then downloaded all the existing model memories along with the new one to my Taranis,hey presto,I have wiped all the models from my transmitter.Now when I connect the transmitter to my PC cannot find it.I read that the SD card may need updating,so I downloaded and installed the latest fimware for the SD card from the FRSKY site.My problem still exists.I cannot get the PC to talk to my Taranis,although it did so to wipe out the model memories.

    • Hi, Barrie!

      You don’t say which version of the firmware you’re running. Is it the original FrSky edition that came on your TX, or is it the developer’s version that you downloaded and installed? If you’re running FrSky, I’m not sure that I can be of much help to you. However, I’ll do some digging.

      If you’re running the Developer’s Version, did you save the models file that you downloaded? If so, you should be able to load them back into your TX with the, “Write Models and Settings” option from the Companion toolbar.

      Sorry for the delay in responding.

      Leonard (mac44mag)

  2. Hi:
    I am sorry if this has been asked, but I have tried to find out which build options are to be checked in opentx when downloading? I skimmed through but did not find it here or on the many forums. Could you help? Do you know if there is a listing of all the different forums and what can be asked on each of them?
    Thanks for any help. I am going through the classes now. I have had my A version radio since before Christmas and still have not flown a plane with it. A lot of pressing buttons and downloading files to look at though.
    Thanks for any help.

    • Hi Don — Here are a couple of links to threads: and There are others that you can find with a Google search, but if you’re just starting, I think you’ll find that the forums are pretty daunting both in size and speed of movement. You can literally spend months in those two threads just trying to cover the ground they’ve already covered.

      Regarding acceptable questions, there’s not much that can’t be asked in the forums so long as it’s on the forum topic, but you’re kinda expected to research your question on the forum search capability before asking something that’s been answered a bunch of times. If you’re just getting started, I think you’ll get more return on your time invested here in the OTXU undergraduate classes. Leonard’s “Fundamentals” classes will give you everything you need to update your software regardless of where you’re starting from. Roger’s classes on Radio Set Up are the next step in learning how to use the radio, and my class on “Basic Airplane Set Up on Taranis” is targeting the new user, like you, who is just starting to learn how OpenTX works. All of those classes are comprehensive works, which means that you’ll spend a lot time working through them, but having done so, you’ll be flying your airplane. They are all built in a step-wise manner so that no one step is difficult.

      Regarding build options –> Most of them are simply owner preferences. Obviously you’ll check the language that you want to use. If you’re not planning to fly helicopter, you don’t need to clutter up your screens with heli stuff that you won’t use, but it doesn’t hurt to have it. Lua is an advanced scripting feature that you don’t have to have as a starting pilot, but again, it doesn’t harm anything to have it. Your Model-A won’t have the haptic capability installed, so you won’t need that, but yep… it won’t harm anything to include it. You’ll find all this and more in Roger’s Radio set up instruction.

      The OTXU was conceived and is being constructed for newcomers to OpenTX on Taranis. Start here, and faster than you’d think, you’ll know more about how to make your new radio work for you than most other users. Welcome to the community. It’s a learning experience, so let us help you along the way. I think you’ll enjoy the process. Regards………….. Bob R.

  3. Ref Lesson Progression – Completely lost at Step6 Question – What ‘Discussion Notes’? Question – where are these located?
    Note: OTxComp V2.0.8 installed on the PC satis.

    • JayDee:

      The discussion notes referred to there are the ones for the next lesson, “Installing OpenTX Comp.”

      Let me know if that doesn’t do it for you.


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