How to Connect/Flash BLHeli_32 ESC via FC Passthrough

This tutorial is written for complete beginners, which explains how to connect BLHeli_32 ESC’s to computer through “FC pass-through”, and how to use BLHeliSuite_32 to flash BLHeli32 firmware and configure ESC settings.

Check out this article if you are new to BLHeli_32, it gives you an overview of the firmware.

Table of Contents

What’s “FC Pass Through?”

“FC pass-through” basically means using your flight controller (FC) as a programming tool to access your ESC’s. This is the easiest way to flash and configure your ESC, because you don’t have to change any of the wiring or take them out of the quadcopter.

Just leave the ESC connected to the FC, plug in the LiPo to power the ESC’s, and plug in the USB cable to the FC, and that’s it!

Download Software

Download the latest BLHeliSuite configurator for BLHeli_32 here:

The link is in the “READ ME” section at the very bottom of the page.

Connecting to BLHeliSuite32

REMOVE YOUR PROPS before continuing.

If you haven’t already, connect ESC signal and GND to the FC. Power up the ESC with a LiPo battery, and plug in the USB cable to the FC.

The software we are going to use to configure our BLHeli_32 ESC is called “BLHeliSuite32“.

In the BLHeliSuite32 configurator, click “Select BLHeli_32 interface” in the top menu, and select the option “BLHeli32 Bootloader (Betaflight/Cleanflight)“.

At the bottom left of the program, choose the COM port of your flight controller in “Port“, leave Baud Rate at default, and click “Connect“.

Once it’s successfully connected, click “Check” and your ESC settings will populate. If you get a warning, check FAQ section.

You can now change settings as you see fit. In this article I explained the BLHeli_32 settings that matter for a 5″ mini quad.

The ESC’s you are working with are numbered.

ESC #1 should be blue, it means it’s the “master ESC”. If you make a change to the “master ESC”, and press the button “Write Setup“, the settings will be copied over to the “slave ESC’s”.

ESC #2, #3 and #4 should be either green or orange – green means they are the “slave ESC” with exactly the same settings as the master. If they are orange, it means they have different settings.

All four ESC’s should ideally have the same settings. If you see an orange number, you should be careful and check. The only exception is “Motor Direction“, sometimes we want to reverse the motor rotate direction. So in this case it’s normal to see an orange number.

You can un-select an ESC you don’t want to change, just click on a ESC number and it will disappear.

Oh, and this is how to use the “Music Editor” so your ESC makes a unique little startup song.

Flashing BLHeli_32 Firmware

When flashing firmware, make sure your computer is connected to the internet! BLHeli32 checks online whether your ESC is legit or not. But changing settings is totally fine without internet, so you can still configure it in the field :)

Make sure your ESC’s are indeed BLHeli_32 compatible. Mistakenly flashing BLHeli_S ESC with the 32-bit firmware can “brick” your ESC and it’s irreversible.

REMOVE YOUR PROPS before continuing…

Connect your ESC’s to BLHeliSuite32 program as I showed you earlier:

  • plug in LiPo
  • plug in USB cable to FC
  • choose the right COM Port, and hit “Connect”

After it’s connected, click the “Check” button. Here you will see the names of your ESC, and firmware version they are on.

Before flashing, Back up your settings! Do this by taking some screenshots for each ESC.

In BLHeliSuite32, click “Flash BLHeli“, and click the button “OK”.

You will be prompted if you want to flash this firmware, click “Yes”

And the flashing will begin, which will take about 30 seconds for each ESC.

When the firmware flashing is done, the program will ask if you want to write current settings to your ESC, click Yes if you want to retain your previous ESC configuration.

When this is done, it will move on to the next ESC. Repeat the same steps you just did until all 4 ESC’s are updated.

When it’s done, click “Disconnect” in BLHeliSuite, unplug your battery and plug it back in to restart your ESC’s. Press the Check button again to confirm the version numbers. (screenshot below might be outdated)

Note that the pop up window also shows input frames, this tells you if DShot is working optimally, “Bad” indicates how many data packets are being dropped. It’s useful for troubleshooting if your ESC’s are working well with DShot. If you get lots of bad frames, try slower DShot protocols, or Multishot, or finally Oneshot125.

Check your ESC settings and make sure they are correct, such as motor direction and other parameters.


I can’t connect to my BLHeli_32 ESC with FC pass-through even with the latest BLHeliSuite32 app. My FC is loaded with the latest BF firmware. However I can connect to other ESC (not 32bit) without problem with the old BLHeliSuite.

Your FC probably has an older Betaflight firmware prior to V3.2. Update your FC with latest BF firmware and try again.

I am getting an error when trying to flash new firmware: “Unable to establish server connection!”.

This error occurs when you have no working internet connection on your computer.

BLHeliSuite32 checks if your BLHeli32 ESC’s are genuine before flashing new firmware to them. No internet, cannot check, and thus it fails.

I am getting an error “Initialization of serial 1wire passthrough or 4way interface failed! Please check Betaflight revision for support of serial 1wire passthrough or 4way interface!”

I was also getting this error when using my Naze32 (F1) flight controller, even with the latest Betaflight installed. I had no way around this error, and I had to use a F3 FC in the end. Maybe BLHeli32 passthrough is not supported in F1 FC’s.

Edit History

  • Jun 2017 – Article created
  • Jan 2018 – Added steps how to flash ESC
  • Nov 2018 – Updated link to download BLHeliSuite32
  • Feb 2019 – Updated instructions and screenshots to the latest BLHeliSuite interface

44 thoughts on “How to Connect/Flash BLHeli_32 ESC via FC Passthrough

  1. Alex

    Is there anyway you can use an ardumino board to unbrick the ESC? I have one (ESC#4) that is not reading and no lights are coming on. I swapped ESC and the problem carried over, so I know it is not a FC problem. I tried soldering a ardumino board to it and the board reads on BLheli, but will not download the firmware. So, I am not sure if the points I chose on the ESC are correct to connect to the ardumino board, but I know ground is good. Any info is helpful, thank you.

  2. Flynn203

    Thanks for posting this and your other reviews, always worth reading and very professional. Even though I don’t fly quads.

  3. Markus

    Hi Oscar, since BF 4 i can‘t connect to the Wraith32 on my 2 Helix‘s (F3..). Up to 3.5.7 everything is fine. Is this a known „feature“ or a bug? Maybe you habe heard something. Thanks, Markus

  4. Claudio

    My quad is Eachine Tyro99 with RC Flysky FS-i6 and receiver FS-iA6B, then the motors turn on all the times but when i tried setup the ESCs show this error: “please check data – und power – connections to the ESC” and the LED on the card stops blinking.
    Please, who could help me?

    Best regards


    1. Oscar Post author

      Did you plug in the battery?
      Are you using the correct configurator? I.E. are those ESC BLHeli_32 ESC? Or BLHeli_S ?

  5. Roger74

    I just wanted to share my experience of how I SOLVED the following error message on BLHeli32

    Serial Interface “m4wFCIntf” connected successfully.
    Connection to ESC#1 failed!
    Please check data- and power-connections to ESC!

    After a couple of hours of trying every conceivable group of options, usb cables, turn BF on, turn BF off, internet search,stand on the table and scream “i cant take it any longer” :) etc,etc, i was ready to give up. And just on whim I thought i would try a different version of BLHeli just to see if it would connect and give me an error message also, Much to my surprise and embarrassment i discovered that i was using the wrong BLHeli version!! But it did solve the question: why am i getting this error..
    I thought the ESC’s on this quad was on BlHeli32 but they are not, my other quad has Esc’s using Suite32. And because it connected to Suite32 i assumed i was using the correct version. WRONG

    So if you get that message make sure you are using the correct version of BLHeli
    Hope this will save someone some grief.

    1. Oscar Post author

      DShot isn’t working as well as expected. In this case try slower DShot protocol, or use Multishot or even ONeshot.

  6. K Raghavendran

    Dear Oscar,

    This is my first Dshot based ZMR250 Build.

    ESC : Blheli 32 Dshot 50A Escs
    FC : Dalrc f405 AIO

    RX and Tx : Trananis X8R and Taranis Q X7

    Problem that I am facing:

    1.ESC emit only 3 Beeps instead of 5 Beeps when I connect my battery.
    2.Motors do not Spin
    3.I cannot connect ESCs to BlHeli Suite.

    Serial Interface ”m4wFClntf” connected successfully
    Connection to ESC#1 failed!
    Please check data- und power-connections to the ESC!

    Where i might have messed up:

    1.Didnt know that Dshot doesnt need esc calibration.
    2.I raised the Throttle Stick high on the TX and connected the battery to the FC like PWM, PPM etc.
    3.After this point, ESC Beeps only 3 Times.


  7. ArcherFPV

    I just finshed a build today and updated to newest betaflight 3.5.3 but when I go to motors tab to test motors, motor 1 isn’t spinning. I go to blheli 32 and it says esc 1 not found. Im running the Dalrc F405 and Engine 40a 4n1 esc. im able to connect to blheli 32 and was able to flash the other 3 escs to the latest fw but of course cant flash esc 1 :-( any insight on what could be going on?

    1. Oscar Post author

      double check ESC connector, make sure the ESC signals are connected to the FC. Otherwise it sounds like a faulty ESC, contact your reseller see if you can get a replacement.

      1. ArcherFPV

        Thanks for the info. It’s taken me 2 months but I finally got the vendor to send me a new one this week. Seems that dalrc didn’t verify that all the esc’s on the board were flashed before they shipped it out. Apparently there were quite a few people with the same issue on the same esc 1. Others it was 2 and 4. Hopefully it doesn’t take a month to get here. I really want to fly that rig.

  8. Wey Fun


    I am using a AirBot’s Omninxt F7 controller with a Racharlance Fort32 40A 4-in-1 ESC. When I connect the controller via USB and power up the ESC with 6S Lipo, the BLHeli32Suite says “Found 2 ESC with similar unique ID numbers!” . The controller comes with Betaflight 3.4.0 so should not be problem.

  9. Benjamin

    I have a kakute f4 Flight Controller (v1 not v2) running/flashed on Betaflight 3.2.0 And im using BLheli 32bit 30 amp ESC’s Running Dshot 600 and when I try/want to connect BL Heli Suite 32 I keep getting the same error which I cannot find a fix using google/forums searches…Help would be greatly appreciated.

    MY error is :
    Connection to 4-way interface “m4wFCIntf” succeeded.
    Found outdated Protocol revision 106!
    Please update the Interface to a supported revision!
    (protocol 107 or higher)
    Now like I mentioned I cannot find a solution to this problem using google searches and multiple forum searches.

    Any insight?

  10. Andrew Brahim

    Oscar, I found your article helpful, but I’ve ran into an issue with the speed controllers not being found in blheli suite. I first thought it was my servo pins on my Sp racing f4…but it looks correct. Also the escs only light up momentarily when I connect the battery but then turn off. I’m running lumenier 51 A x4 and a 6S battery. I’m trying this with no motors connected…could that be the cause of my error?

  11. confidentcar .

    I was setting up a lumenier 4 in 1 esc 35 amp but by mistake i opened it with blheli s instead of blheli 32 and i flashed the latest blheli s version therefore i briked the esc. Now when i connect blheli 32 it recognize that it has a corrupted file and it tries to erase it but is unable to complete the process, i can not find the proper .hex file to download and manually. Do you have any suggestions?

  12. Rob

    I am constantly getting an error message whenever I try to Read Setup.
    It states
    Serial Interface “m4wFCIntf” connected successfully.

    Connection to ESC#1 failed!
    Please check data- and power-connections to ESC!

  13. nick murphy

    i just wired my “makerfire blheli_32” esc’s to a bff4 board and in blheli 32 suite its saying connection to flight controller failed check usb serial port and power connections. my wiring is good and i have bf 3.2 flashed already. the motors spin from the motor tabs so i know theyre connected. what do i do?

    1. Oscar Post author

      Are you powering up the ESC’s with battery before connecting?
      Also check with Makerfire if they are actually open for connecting to the configurator.
      I had some ESC’s from DYS and that batch was actually locked and i was unable to connect to BLHeliSuite with them.

  14. -G FPV

    Oscar, I’ve been working on new build using the Betaflight F4 along with the Betaflight 32bit 35a ESCs. While in the Betaflight program all four motors spin up correctly and everything seems fine. Turtle mode will activate however the motors do not spin backwards like they should. I’ve downloaded BLheli_32 to try to reflash the ESCs but ESC number four is intermittent and ultimately not found in BLHeli_32 when singled out. I’ve reflashed my FC with the lastest stable version of Betaflight 3.2 and still running into the same problem. Am I over looking something?

  15. phillip pedigo

    Naze32 Rev 5 – BetaFlight 3.2.1 – I am getting an error when i Read Setup on BLheli Suite. Plug in USB to FC then “Connect” in BL heli suite, then plug in batter, then hit “Read Setup”. No worky. “Found Multiple ESC Configuration in SiLabs mode: ESC# 1: –“. I have tried flashing the FC with Betaflight 2.7 (read this in a post and it seemed to work for the guy) still didnt work. Using BLHeli suite 16 and 32 both come with error. Please help!

  16. Jon

    Thank you for the education and walkthrough Oscar. I put it to use tonight and managed to configure everything successfully on my first set of 32b ESC’s :)

  17. ChuckH

    Hello Oscar,

    So I am trying to setup my flight controller and esc’s and am having a hard time getting everything set up. I am new to all this quad stuff so bear with me. I have flashed my FC Naze32 with cleanflight 2.1 and I have been tryiing to setup my esc’s with BLheli suite. If I am not using Betaflight 3.2 should I be using the BLheli suite16 instead? When I attempt to connect to my esc’s with the BlHeli configurator they do not connect at all. When I use Suite32 it kind of connects meaning Suite 32 will read the esc’s and it knows that there are four, but it will not spin them up or allow me to make individual adjustments and such.

    I am sure i need to back up a step to get everything working, what suggestions can you give me?

    1. Oscar Post author

      No, “BLHeliSuite_32” is for 32-bit ESC’s, and you must have the latest Betaflight 3.2 installed on your FC.
      If you are not using 32-bit ESC then just use “BLHeliSuite”, and it should work on Cleanflight and older BF firmware.

  18. Danny

    i have the Matek F405 FC and cant connect to BlHeli32 suite im getting the :

    “Initialization of serial 1wire passthrough or 4way interface failed! Please check Betaflight revision for support of serial 1wire passthrough or 4way interface!”

    ive tried everything and i have same setup on another quad and no problems at all
    motors spin fine but the escs will not connect to Blheli32 suite

    any help?


  19. Bryan D Wolfe

    My ESCs program in BLHELI_32 fine, but when I use the motor tab in BetaFlight Motors 1-3 spin fine but NOT motor 4. The ESC LEDs are on, it reads and programs fine, swapped motors to a knowing working motor, swapped ESC from its original position of 1 to now 4 and same issue. Any idea what is going on?

    1. Oscar Post author

      The LED only indicates the ESC is getting power. My guess is that your motor output on the FC is bad..
      if you have a spare motor pin, use it.

    2. Dirk

      Similar issue here. With using dshot150 only motor 1-3 are spinning.
      BUT if I disconnect the receiver (MPX) everything works fine!
      So the XBUS_MODE_B seems to disturb the communication with the ESC. Also the motor setup with the suite does only work properly without receiver connected.
      Multishot is working also with receiver on…

  20. Oyvind

    Trying to connect to my Littlebee Summer 2-6s BLHeli_32 30A esc’s from the latest BLhelisuite. I am not able to load BLheli32 interface profile, Cannot read settings, or flash firmware. All motors spin in the motor test just fine. Also in Betaflight.. I have flashed my FC to Betaflight 3.2 RC4, so it should be fine. FC is Matek F405-AIO. Any ideas?

  21. Daniel

    My first comment here and would like to thank all the people that invest their time to make this site happen. I’m new to the hobby and many times this site guided me along through the steep learning curve for a beginner like me. Great job!

    I’m trying to test my motors using BF or BLHeliSuite32 but I cannot make them spin. Previously, on BF v3.1.7 I was able to go in motors tab and spin just 1 motor ( from 4 ). Later I discovered that ESCs where taking a lot of time to get “read” by BF as eventually I could spin 3 motors. I kind of gave up on the last as it was taking too much time.

    After the BF update and even on BLHeliSuite32, there is no way I find out how to make motors spin from the “motors” tab. On BF sliders are disabled and it won’t work on BLHeliSuite32, although it says that it can read setup for all motors. Is this bad and if so, is there any reason why this might be happening? I’m afraid something is wrong with my ESCs or my setup.

  22. casey hanke

    Anyway to do this with raceflight? I have the new skitzo board and im trying to get raceflight to see them

    1. Pyrolassist

      Am I also building a new quad with Skitzo (Raceflight) and was wondering the same? Has anyone successfully used BlHeli_32 and raceflight together?


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