Flashing OpenTX

Flashing OpenTX Companion


Note:  This lesson is written for those who DO NOT already have v2.0+ on either their computer or their radio.  If you've already flashed v2.0, then you have two methods of updating available to you, both involving OpenTX Companion.   A) Just as you did the first time with the TX off (uses the Zadig driver), and B) Automatically through OpenTX Companion with the TX on in Bootloader mode.
The major difference is that when updating with the TX off, you also update any changes to the bootloader, while when updating with the TX already in Bootloader mode you update only the firmware, not the bootloader. The choice is yours.
NOTE:  It has been reported by Taranis Plus users that after installing Companion, it downloads the latest version of OpenTX for the Taranis, NOT the Taranis Plus. If you own a Plus, be certain that you download the firmware for the Plus, not the original Taranis.

Click Part 2-Flashing OpenTX Companion for a .PDF copy of this lesson.

Downloading OpenTX Firmware

  1. If you left the option to start OpenTX selected, OpenTX will wake itself up, stretch a bit, then inform you that a newer version of OpenTX is available. Notice the last button on the bottom right of the notification window, “Release Notes.” When I flash a new version of the software, I’ve always found it helpful to check them out. Sometimes I don’t understand them, but I check them out anyway. The screen displays, “Do you want to download it now?” Obviously, you do, so you click “Yes.”CTXnew_otx_w
  2. A “Save As” screen opens, asking you where you want to put the firmware. I’m old, and I get confused a lot, so I’m somewhat anal in how I do this. I’m always afraid that if, for some reason, I want to revert to a previous version of OpenTX, if they’re not in the same place and labeled properly, I won’t be able to find them. Accordingly, I’ve created a special folder called “v2.0 Firmware” and put all of my downloaded OpenTX files there. By the way, OpenTX firmware files all have a “.bin” (binary) file extension. Oh, yeah, there are all kinds of things listed in the file name, such as “noheli”, “en”, etc. For now, just accept the default and move onward. You’ll learn how to customize your firmware downloads in another lesson.CTXsaveAs_w
  3. You can rename the file, or add an identifier. I use: XX-XX-2014, with the X’s representing the month and day. Your scheme is entirely up to you, of course.
  4. Once you have the filename the way you want it, click “Save” to save the file.
  5. The download will complete, and you’ll see the following screen:


Have you backed up your existing firmware and the EEPROM?

If you have not yet backed up your existing firmware and EEPROM, click “NO” to cancel the firmware write. You really need to have a copy of the existing firmware and your existing EEPROM, even if you’ve never flown off of the transmitter, in case anything goes wrong. Don’t worry! After you’ve backed up those two files, we’ll finish flashing the new firmware.CTXflashNow_w

OpenTX Companion Firmware Flash Confirmation Screen

Backing Up the Firmware

  1. After you terminate the flash operation, you’ll see a blank OpenTX Companion screen. Select either Read/Write from the menu bar at the top then select “Read Firmware from Radio”, or, select the corresponding transmitter icon in the Read/Write toolbar.CTXmenuBar_w
  2. A screen will open asking you where you wish to save the file. Again, since I’m getting old and forgetful, I need to lable things clearly and put all of them in the same place. As you can see, I’ve created a folder called v2.0 Firmware on my machine, and all of my firmware files, both backups and downloads, go in there. I’m considering creating another folder for just backups under the Firmware folder at the same level as v2.0 Firmware.CTXfirmwareSave_w
  3. Enter a descriptive name for the file. I like to use dates to help me keep things in order, and since I’m in the US I tend to use the mm-dd-yyyy format. Feel free to do as you wish. To me, a great name for this file would be: 06-22-2014-OEM_FrSky_firmware.
  4. Enter the filename and click “Save.”
  5. You’ll see a standard progress bar, then when the operation’s complete, the blank OpenTX Companion screen. Once again, no pleasant, reassuring message that everything went well, no best wishes for a good day, nothing! As user friendly as everything else is about OpenTX, I’m beginning to think that the STM chip is like the grumpy family uncle.
  6. Use Windows File Explorer (or whatever you’re using to view your computer’s file structure) to navigate and open the folder where you stored your backup file. It should be there.CTXfirmwareSave2_w
  7. OK, that takes care of the firmware. What about the EEPROM? You DID back it up in Companion 9X before your started, right? You don’t want to risk losing all of your work in case of a, er…., setback. You didn’t? In that case, forge onward!

Backing Up the EEPROM

  1. Make certain that your TX is ON in bootloader mode and plugged into your computer.
  2. Open up OpenTX Companion and either select: Read/Write –> “Read Models and Settings readEEPROMfrom Radio”, or click the first downward pointing green arrow in the icon toolbar. Note that this is a different icon from the one used to back-up the firmware.
  3. If you see this image, check to make sure that your radio is actually on in bootloader mode and connected to the computer. No, you may NOT ask how I know that!CTXnoRadio_w
  4. OpenTX Companion will read the contents of the EEPROM currently in the TX, and open it for you to see. It contains all of the settings and model specifics that you are currently working with.CTXeeprom_w
  5. From here, it’s a common “Save as…” operation.
    1. Create a folder with a descriptive name. Something like, maybe, EEPROMS?
    2. Click in the EEPROM title bar (where it says “document1.eepe”)
    3. Then click: File à “Save as…” in the menu bar.
    4. Windows will ask you where you want to save it and what you want to call it.
      1. Make sure that you’re in the folder where you want to save the file.
      2. Give the file a descriptive name, including the date
    5. Click “Save” to save the file.

Now that you’ve got your backups safe and sound, let’s finish flashing the firmware!

Finishing Up: Writing/Flashing the Firmware (continued)

  1. Return to OpenTX Companion
  2. Click the transmitter icon with the red flame in the icon toolbar.writeFirmwareTX
  3. Be careful! If you foul this part up, you will NOT be a happy camper. Your flash operation will fail if all of these things aren’t correct before you click the button!
    1. Make triple sure that your transmitter is OFF.
    2. Check to see that it’s still plugged into your computer, on both ends of the cable. Hey, plugs fall out, you know!
    3. Check to see that the STM BOOTLOADER still shows under Universal Serial Bus devices, not Universal Serial Bus controllers, just above it in the Device Manager. If you left your Device Manager window open as directed in Part #1, this step is as simple as clicking the Device Manager button in the taskbar.
    4. If all of the above items check out, click “YES” to start the firmware flash.
  4. The next screen is the “Write firmware to Radio” confirmation screen. It lists the version you’re flashing, the varient (Don’t ask me! I haven’t got a clue.), and the date and time. It’s also the window where you can elect to use a start screen other than the default Open-TX one. We won’t mess with it at this time, so leave everything as it is. This is your last chance to bail out by clicking the “Cancel” button, but we’re brave! We’re intrepid! Of course, we’re also a bit nervous, so ask whomever you believe in to be by your side, then click the “Write to TX” button.CTXflashConfirm_w
  5. The flash operation will proceed (You’ll see the traditional Progress Bar), and at its conclusion, the OpenTX Companion screen just goes blank. That’s right, no confirmation message, no “Thank you for stopping by, have a great day.”, nothing. Nothing but the standard grey desktop with the OpenTX Companion menu and toolbars across the top just like you’ve had since the first time the program fired up. Not to panic. The fact that you didn’t get an error message is a very good thing!
  6. VERY IMPORTANT!!  If you are upgrading, as we are here, with the TX connected to the computer in Bootloader mode, make sure that you take the extra ten seconds and use the “Safe Disconnect” feature of Windows BEFORE you unplug the USB cord!
    While I, personally, have never experienced it,others have reported that failure to use Safe Disconnect can result in a corrupted SD card, and trust me, that WILL ruin your day!
        1. Click the “Up” arrow to open more tray icons if the “Safe to Eject” icon is not visible.

    safeEject2wSafe Eject Button

     2. The detected devices will show.  Click, “Eject FrSky Taranis Bootloader.”

    scottEjectClick to Eject the Taranis

     3. When you see the screen below, it’s safe to disconnect your transmitter.

    safeEject3wIt Is Now Safe to Unplug  Your Transmitter

  1. Disconnect your TX and power it off.

However, DON’T turn your radio back on, yet. You need to know what to expect before you do.

OpenTX v2.x uses a different format for the EEPROM. That’s the file that contains all of the information about your individual models. After you’ve updated to v2.x, your Taranis tries to read the EEPROM that it already has stored but can’t, because the new firmware won’t recognize it. As a result, you get a message stating that you’ve got a bad EEPROM and that the EEPROM’s being reformatted!

Needless to say, this has scared the daylights out of a good many folks, especially since the first time you do this you’re normally a bit apprehensive. Not to worry. OpenTX simply converts your old EEPROM into the format used by the new firmware, and you’re in clover. OpenTX Companion also converts any models you move from an old format EEPROM to a new format one when you work on them. Yes, there are a few things that might not convert exactly as you expect, but if you’re a first time user (as we specified in the beginning) you probably won’t have anything in the EEPROM anyway, and no models need to move from Companion 9X. There is a factory supplied EEPROM, and it will reformat.

Now that we’ve gotten that out of the way, let’s check to see if we’ve actually got our new firmware!

Verifying the Firmware Flash

  1. Power your Taranis on normally, not in bootloader mode.
  2. You’ll see the “Bad EEPROM” thing, and the EEPROM will reformat. Don’t worry about it. We’ve already discussed it.
  3. Clear any warning screens that might show after the EEPROM format by pressing any key.
  4. Press and hold the “ENT” key to enter Radio Setup. My advice would be to not make any changes here until you have a chance to go through at least the next lesson, Check it Out!, or preferably, not until you get into the next class, Radio Setup.
  5. When you see the Radio Setup screen, short press (tap, don’t hold) the Page key three times to get to the Version Page. You should see something similar to the screen below, but the actual version number will probably differ because you just KNOW that the developers are improving OpenTX all the time.ver203_w
  6. After you’ve verified that you actually have the new firmware, press “EXIT” to get back to the main transmitter screen.


I really hate to tell you this, but what the heck! Notice the bottom line on the version screen? That’s right! Once you have v2.x on your transmitter, you can back up your EEPROM from the TX directly to the SD card. Some pilots use this to make sure that they always have a spare copy of their active EEPROM in case they get wild with modifying the active one at the field and somehow or other (you fill in the blanks here) need to go back to the one they started the day with. If you’re using OpenTX Companion, you should always have a backup copy of your EEPROM on your computer, but it’s generally not at the flying field, although more and more folks are packing their laptops along with their toolbox and plastic bags for parts retrieval. If you have a working copy on your TX, you can restore it from backup. You do that from the boot loader screen.


That’s about it for this one……finally! (Handel’s Hallelujah Chorus playing loudly in the background)


This one was a long haul.  Thanks for hanging in there. You now have the new firmware on your Taranis. The good news is, I dare say that your perseverance has not only helped you to write OpenTX v2.x to your TX, but it’s also rewarded you with a better understanding of one of the more confusing segments of OpenTX than many users can claim. Now, it’s time to check things out and see if everything went as well as it seemed to by moving on to the Check It Out! lesson, or, if you’re one of those people who excel by doing Extra Credit, check out the Bootloader Basics page.


Flashing OpenTX — 31 Comments

  1. Here’s my situation. I have a Taranis plus that I bought with 2.0.9 firmware. I learned how to install and run Companion. I have been creating/editing/saving/transferring eeproms back and forth. In spite of all that, I’m still relatively green and came here to try to understand about upgrading existing 2.0.X firmware. But nowhere can I seem to find an answer to this hankering question:

    If I update my firmware, does it wipe the eeprom from the radio? I know it says they are seperate. I see it’s best to back up old firmware/eeprom prior to upgrading firmware. I currently have a splash screen that I like and at this point I don’t know how to get it back if it’s also wiped. Fundamentally speaking, will the firmware upgrade leave all my models, settings, calibration, sounds, splash screens alone? I keep getting reminded of firmware updates. Is it best practice to save model settings, do firmware update, and send saved model settings back to Taranis? It looks like there is a spot to pick splash screen. Problem is, I don’t know where my custom splash screen is to pick it.

    My latest reminder is 2.0.12 I would like to do this but don’t want to screw up my models/settings in the process. I want to avoid trying to fix something that doesn’t really appear to be broke. I read the release notes on the 2.01.12 improvements. So I guess that means it really should be done. I just don’t want to wreck anything. 🙂

    • Good questions, all! Let’s see how many of them I can answer.

      Re: EEPROM….. No, writing the firmware doesn’t wipe out your EEPROM. However, you sound as if you’ve been around this stuff enough to know that “stuff” happens. I never write firmware without backing up my current version and the EEPROM. Better to be safe than sorry.

      Re: Start screen….As far as I know, the only way to change the start screen is through Companion in: Settings –> Write Firmware to Radio (see image: Splash Screen) You’ll see that you have three options:

      1. Use firmware start screen….this is the default OpenTX splash screen and will be used unless you change it.
      2. Use library start screen….If you select this option in Companion, you’ll be presented with a series of choices that are already available to you. I don’t know where they’re stored or how you can access them, and quite frankly it doesn’t matter to me. When I use one, all I do is select the image I wish to use and it magically appears after I’ve updated my firmware.
      3. Use another start screen….If you select this, you’ll be prompted to select a start screen image from your computer. When you write the new firmware, it’s there, assuming that the image meets whatever requirements OpenTX has for start screen display. I don’t recall what they are, but hopefully someone else out there or in one of the Groups can help you out.

      Hope this helps!

      Leonard (mac44mag)

      • Thank you very much…good answers. One more uncertainty that I failed to mention and I’ll be all set:

        Radio calibration values…Here’s my understanding of how this works; I do a stick cal on the radio. Those settings are held in the radio UNLESS I check the box to transfer radio profile. Is this correct or am I in left field on this? The reason I ask again has to do with firmware update. How can I make certain I have the current stick cal on my radio. This might not be a big deal for many. But I fly with three different Eagle Tree Vectors. The Vector uses my stick cal when I configure the Vector. Otherwise, I will need to perform a RX calibration for all my Vector models. And this can throw off all my in flight trim settings specific to each Vector. I think I know what you are going to say regarding ‘stuff’ happening. It almost sounds like in order to be positive my stick cals will be correct, is to start over and re-calibrate all my Vector models. The concern is that it could take several Vector flights on each model to get it tweaked back in. I just need to know if this is what I can expect on any firmware update using flight controller/stabilzers. Sorry for all the long winded stuff. My current skill set includes overthinking and apprehension. 🙂

        • This is must me, but whenever I update my firmware, I ALWAYS do a TX calibration, download the installed EEPE file and open it, then click “General Settings” in the EEPE window and select, “Store calib. and HW settings in selected profile.” I had folks tell me that it’s essential and others say that it’s not. All that I can tell you is that I feel more comfortable doing that and knowing that I’ve gotten valid calibration data in Companion.

          Like I said, just my 2 cents worth.

          Leonard (mac44mag)

  2. Hi, i’m sure i’ve done some mistakes during taranis plus flashing.. mmm..
    now, when i switch it on, the alarm buzzer loudly scream at my ears and the screen is blue and empty!
    the voice said:”welcome.. bla bla”, but everytime I touch something, the buzzer starts again..sad me..

    How I can reset to defaults or solve this issue?

    • If you used Companion, check Settings –> Settings in the main menu to see if you’ve got “OpenTX for FrSky Taranis Plus” selected as the radio type. If not, select it, download the correct version of firmware, and re-flash the TX. If that doesn’t work, try: http://open-txu.org/?p=3387.

      Hope this helps!

      Leonard (mac44mag)

  3. The one thing that I didn’t read anywhere in this upgrade howto was the fact that if you have a Tx on an old version (r2490? etc) then you must use the old Companion 9x to install the initial version 2 firmware. Then you can use OpenTx Companion and uninstall the old Companion 9x. This instruction intimated to me that you could do it all via the new OpenTx Companion but the firmware install fails. Did I misread something? Other than that thanks for the great howto!

    • Please check Undergraduate Courses –> Fundamentals of OpenTX (Win) –> Using Zadig, Note #1 at the top of the page. That explains that the only way to upgrade from a pre v2.0 version of OpenTX or from another firmware such as FrSky original pre v2.0 is to use Zadig.

      Thanks for stopping by!

      Leonard (mac44mag)

  4. Mr MacKey,

    I did find a drop down list in the settings menu listing the Plus.
    A follow up question is – should the following options be checked or not in the settings?
    _Append version number to FW file name
    _Offer to write FW to Tx after download
    _Enable automatic backup before writing firmware

    Thank you,


    • Hi!

      A) My personal opinion is that I want the version number appended to the download. It helps keeps things straight in my addled brain.
      B) If you normally write the firmware immediately after downloading, leave it checked. It’s totally up to you.
      C) I also keep the auto. backup feature activated. You never can be too safe with this stuff! 🙂

      Hope that helps!


  5. Mr MacKey,

    I have a Taranis Plus I received 3 days ago (whoohoo!). I saw your caution above:
    “NOTE: It has been reported by Taranis Plus users that after installing Companion, it downloads the latest version of OpenTX for the Taranis, NOT the Taranis Plus. If you own a Plus, be certain that you download the firmware for the Plus, not the original Taranis.”

    I cannot discern where in OpenTx is tells me if the firmware is for Taranis or Taranis Plus and therefore, I’ve not updated from v2.0.9 to 2.0.13 yet. Where does OpenTx tell me its for the Plus?



    • Have you run the Zadig install? That seems to be the one that works best for most folks. Just checking. Also, which version of OpenTX are you coming from?

      • thanks for the reply yes ran latest zandig a couple of times tx is a year old works well verv1.1.02 don’t want any mishaps that’s why I would like to upgrade thanks tom

          • have tried everything but the laptop new leads ect. I give up as it works ok seems others have a lot of problems with these up dates also.
            just hope no surprise loss of control when flying as stated by scott page.
            thanks tom

  6. There is a critical step you need to add for Taranis Plus owners. Be default, after installing CompanionTX, it’ll download the firmware for the regular Taranis. This will load to the transmitter, and it’s not pretty! The display stayed lit up, and the audio screeches like a banshee.

    The Taranis Plus user needs to configure TXCompanion to indicate the transmitter is a Taranis Plus. This can be done in the Settings Menu. I’d add a screen shot, but I guess comment uploads don’t allow that here.

    • I’m glad I backed up prior to attempting to installing 2.0.13. My new Taranis Plus arrived with 2.0.9 and when I first attempted to upgrade to 2.0.13 I didn’t realize that TXCompanion was configured for a Taranis. It did exactly as you stated….screeches, vibrates with nothing on the display. Fortunately I was able to restore the backup of 2.0.9. I then reconfigured TX Companion and pulled the Taranis Plus version of 2.0.13 and installed. Works like a champ.

      • Hi, Kevin!

        Rest assured, you’re not the first one to have that experience. 🙂 You’re in good company!

        Glad it worked out for you.

        Leonard (mac44mag)

  7. I believe this is what happened to me. I didn’t see the second drive and only ejected one. I can’t find any way to get this resolved and I have not seen anywhere on this site to ask what to do. If someone has had this problem and figured out how to fix it can you please post that.

    “While I, personally, have never experienced it,others have reported that failure to use Safe Disconnect can result in a corrupted SD card, and trust me, that WILL ruin your day!”

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