Background

The FrSky X-Series Receivers (RXs) are updateable with new firmware versions that can add new features or correct errata. This guide illustrates how to upgrade a few of the common X-Series RXs by using a FrSky Taranis to apply firmware updates.

Before We Start…

The 3 high level steps you need to accomplish to get your FrSky recievers flashed are 1. Create the correct wire harness 2. Download the correct firmware and get it into place on your Taranis radio SD card and then 3. Flash the device.

The wire harness has one side connected to the Taranis module bay pins and the other side connected to the appropriate pins on your X-Series RX.

The following sections show the connector ends that will work for a few of the X-Series RXs.

NOTE: Pay close attention to the wire layout in each connector. Wires connected to the wrong pins can quickly short the RX; rendering it useless.

Taranis Module Bay Connector and Wire Placement

Connector orientation to the Taranis module bay

Taranis module bay connector

The connector on the Taranis side requires three wires in the following order from bottom pin, to the third pin up from the bottom, in the module bay.

Bottom Pin: Signal (yellow) (connected to the S.Port pin on the RX)
2nd Pin from Bottom: Ground (black)
3rd Pin from Bottom: Power (red)

The Taranis module bay connector figure illustrates the pins used and the layout of the wires in the connector that goes into the Taranis module bay.  NOTE: The yellow wire is connected to the bottom pin in the Taranis module bay.

R-XSR / XSR / X4R / X4R-SB Connector and Wire Placement

The connector that goes into the receiver will have three wires. WARNING, positioning the wires on the wrong pins could short the RX.  The FrSky receiver pinout figures show the pinouts for the R-XSR, XSR and the X4R/X4R-SB.  Notice that the receiver side of the flashing wire harness is identical on the RXSR and XSR while The X4R receiver is a little different as the X4R/X4R-SB pinout figure shows.

Double and triple check that the wires going to the receiver to ensure they follow the pinout diagram. It’s best to use the diagram from the manual you received with the purchase of your receiver.

When referencing the receiver side of the wire harness, the BLACK wire lines up with ‘GND” on the RXSR and XSR and ‘ – ‘ on the X4R/X4R-SB.  The RED wire lines up with ‘+5V’ on the RXSR and XSR and ‘+’ on the X4R/X4R-SB and finally the YELLOW wire lines up with ‘S.Port’ on all three receivers.

FrSky Receiver Pinouts

FrSkt XSR pinout

FrSky RXSR pinout

FrSkt XSR pinout

FrSky XSR pinout

Frsky X4R/X4R-SB pinout

Frsky X4R/X4R-SB pinout

FrSky RXSR and XSR wire harness receiver side photos

RXSR wire harness receiver side

RXSR wire harness receiver side

XSR wire harness receiver side

XSR wire harness receiver side

Taranis to RXSR/XSR flashing wire harness

Taranis to RXSR/XSR flashing wire harness

Get The Correct Firmware And Transfer It To Taranis SD Card

Flashing firmware onto your FrSky X-Series RX requires the firmware to be saved to the SD card in the Taranis.  You want to check, and then double check, that you select the correct firmware for receiver.  After you’ve downloaded it to a known folder on your local drive, you’ll then want to transfer it to the folder on the Taranis SD card.  Here are the steps to make that happen.

FrSky download page example

FrSky download page example

  1. In your web browser, navigate to the FrSky X-Series RX page for the receiver you will be upgrading
  2. Click on the Firmware dropdown arrow as shown in the FrSky download page example figure
  3. Click on the Download button and save the firmware file to a folder on your local hard drive. Make sure you note the file name (i.e. R-XSRLBT171103.frk in the case of the RXSR firmware)  and which folder you put it in
  4. Enter Boot-Loader mode by holding in the horizontal trim buttons (below the sticks) AND, at the same time, powering on the Taranis.

    Taranis SD Card Root Folder

    Taranis SD Card Root Folder

  5. Connect the Taranis to the computer via the USB to mini-USB cable that came with the radio
    • In your operating system’s file browser (File Explorer for PCs and Finder for Macs) the SD card in the Taranis will show up as an external drive. There are probably two partitions that were added as drives and the SD card partition that we are interested in looks like the Taranis SD Root Folder figure shown (Notice the Taranis SD card is showing up as a USB Drive)
  6. In file browser, navigate to the location on your computer’s hard drive where you downloaded the FrSky X-Series receiver firmware update file and copy it (Highlight the file and do a CTRL-C)
  7. In your file browser, navigate to the FIRMWARE sub-directory on the Taranis SD card as highlighted in the Taranis SD Card Root Folder figure shown (Double click on Firmware folder to enter that directory)
  8. Create a sub-directory, inside of the Firmware directory for your firmware updates (Look to the Firmware folder subdirectories figure to see examples of the different folders created to hold each Receiver’s specific firmware file update)
  9. Navigate to the sub-directory that represents name of your FrSky receiver and paste (CTRL-V) your receiver’s firmware file (Notice the example in the RXSR firmware file figure)
  10. On most modern operating systems, you will need to ‘eject’ the Taranis SD card to ensure a safe disconnect
  11. Disconnect the Taranis’s USB cable from the computer
  12. On the Taranis menu screen, navigate to the Exit menu item and click the ENT button (Everything is now in place to flash your receiver)

Firmware folder subdirectories

Firmware folder subdirectories

RXSR firmware file

RXSR firmware file

BootLoader Exit

BootLoader Exit

Flash The FrSky Receiver With New Firmware

At this point, you have made the wire harness and got the correct firmware for your receiver in the right folder to flash.  For the remainder of this procedural guide, we will assume that the RXSR is the receiver we are updating.  The same steps will apply, if you are updating the other RXs.  Only the folders and specific files will change.  The proces is the same.

    1. Power cycle the Taranis
    2. Long press the Menu button to enter Radio Setup
    3. Short press (click) the Page button to enter the SD Card screen and then click the minus (-) button until [FIRMWARE] is highlighted as shown in the Taranis SD card Firmware directory figure

      Taranis SD card Firmware directory

      Taranis SD card Firmware directory

    4. On the Taranis, short press the ENT button to enter the firmware directory
    5. Now you are in the Firmware folder on the Taranis SD card.  Highlight and click on the RXSR directory to enter that folder as shown in the Taranis RXSR subdirectory folder figure

      Taranis RXSR subdirectory folder

      Taranis RXSR subdirectory folder

    6. Select (highlight) the .frk firmware file using the (-) button until the firmware file for the receiver is highlighted as shown in the RXSR Firmware file to update figure

      RSXR Firmware file to update

      RSXR Firmware file to update

    7. Long press ENT button to get to a menu of firmware flashing options
    8. Press the minus (-) button to highlight the Flash External Device menu item as seen in the screen shot below

      Flash external device option !!!

      Flash external device option !!!

    9. On the Taranis, click the ENT button to start the firmware update
      • A progress bar will indicate the status of the update
      • You can watch the LEDs on the FrSky X-Series receiver blink as the update is in progress

When the firmware update is finished, you can disconnect the receiver from the wire harness. You have now successfully flashed the firmware on your FrSky X-Series receiver!

Technical review by: Michael Renish