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How to Flash Firmware of ELRS RX/TX

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  • Kevin Wgl


    I try to flash my RX via Betaflightpassthrougt, and i have this message :

    A fatal error occurred: Failed to connect to ESP8266: Invalid head of packet (0x38)
    *** [upload] Error 2

    The led flash slowly and i dont see any wifi from the RX. Did i something wrong?

  • Kathy

    @Kevin Wgl 

    Hi Sir,
    The article about "How to Flash Firmware of ELRS RX/TX" has been updated. Please check it and try again.
    If it still fails to work, welcome to submit a support ticket to get help. Create a new ticket
    Please attach a video about your operation when you open a ticket. Hope that can help you.
  • Michael Ford

    Has anything changed for elrs v2? I'm unable to update my elrs aio rx with these instructions. BF passthrough fails.

  • elpinguinofrio

    I just bought new HX115LR and I can't even fly this thing because your tutorial doesn't work!



  • alessandro

    hi, I have a problem with your nano module and the 900 receiver. I have flashed both of them with the same version, the latest. The bind works but the flight distance is very short, it goes in faisafe at 1 km !! I updated the Taranis x-lite radio and uploaded the new LUA file as recommended. Everything seems to work but the distance is bad. What do you recommend to do? thank you

  • Roman


    flashing my Lite RX/2.4GHz via Betaflight passthrough, gives me following error:

    A fatal error: Failed to connect to ESP8266: Invalid head of packet (0x80)

    The led is steady blue. ELRS version is 1.2.0. FC is GEPRC GEP-F4-12A.

    Thank you 

  • Nick Whitehead

    Just received 2400MHz Tx Micro module. Tried to build and flash it (2.5.1) via USB, fails on upload:

    Configuring upload protocol...
    AVAILABLE: esp-prog, espota, esptool, iot-bus-jtag, jlink, minimodule, olimex-arm-usb-ocd, olimex-arm-usb-ocd-h, olimex-arm-usb-tiny-h, olimex-jtag-tiny, tumpa
    CURRENT: upload_protocol = esptool
    Looking for upload port...
    Using manually specified: COM11
    Uploading .pio\build\BETAFPV_2400_TX_MICRO_via_UART\firmware.bin v3.1
    Serial port COM11
    A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header
    *** [upload] Error 2
    ========================= [FAILED] Took 83.58 seconds =========================
    Environment                     Status    Duration
    ------------------------------  --------  ------------
    BETAFPV_2400_TX_MICRO_via_UART  FAILED    00:01:23.579
    ==================== 1 failed, 0 succeeded in 00:01:23.579 ====================

    COM port is right, driver is right, tried multiple times on different USB ports and two computers. Tried booting Tx with different internal pushbuttons depressed as per some YouTube videos. Never worked.

    Considered trying to flash via WiFi, but ELRS network never showed up with any reliability.


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