Struggling with a non-responsive ExpressLRS receiver after a failed firmware upgrade? Or maybe you're stuck because FC Passthrough or WiFi flashing isn't an option no matter what motors you eqquipped with such as 4600KV burshless motormeps 2408meps 1804.. This tutorial offers a solution: flashing your ExpressLRS receivers through UART with the help of an FTDI programmer, focusing on the Radiomaster USB UART Flasher for this task.

Advantages of FTDI Programming for Firmware Restoration

When conventional methods like Betaflight Passthrough or Wi-Fi updates fall short, possibly corrupting the bootloader, FTDI programming steps in as a reliable alternative. This approach, independent of flight controllers or Wi-Fi, is a versatile fix for all types of ExpressLRS receivers, offering a universal solution for firmware issues.

Choosing UART Flashing for Stability

The direct connection offered by UART flashing through an FTDI dongle is more than just a backup plan. It provides a stable and reliable link for firmware updates, simplifying the process and reducing the risk of further complications.

Setting Up Your FTDI Programmer

  1. Locating the COM Port: Start by finding the COM Port listed in the ExpressLRS Configurator once you've connected your FTDI dongle to the computer. You may need to manually install the cp2102usb driver if the COM port doesn't automatically show up.

  2. Ensuring Driver Compatibility: Automatic driver installation might cover most users, but if your system doesn't recognize the dongle, manually installing the cp2102usb driver will enable communication between your PC and the FTDI dongle.

Preparing Your Receiver for FTDI Connection

Activating boot mode on your receiver is necessary for FTDI flashing. This can typically be done by pressing the receiver's boot button while connecting it to your dongle. Alternatively, some receivers might require you to temporarily bridge two solder points.

Boot Mode Activation Steps

  • Button-Activated Receivers: Hold the boot button as you connect your receiver to the FTDI dongle. A lit LED indicates that boot mode is active.
  • Solder Bridge Receivers: Bridge the necessary solder points, connect the receiver to your dongle, and then remove the bridge once the LED lights up.

Configuring Firmware with the ExpressLRS Configurator

With the standard setup in the ExpressLRS Configurator, select your desired firmware version, receiver category, and model, making sure to set the flash method to UART. This ensures the firmware is correctly matched to your receiver's specifications for smooth operation.

Firmware and Configuration Selection

Selecting the appropriate firmware and settings is crucial. Incorrect choices could lead to performance issues or the need for re-flashing. The configurator's interface helps guide you through making these selections precisely.


Implementing the Firmware Update

Hit ‘Build & Flash’ to start updating your firmware. Once the process successfully concludes, you can detach your receiver from the FTDI dongle. This step compiles the new firmware and applies it to your receiver, ideally ending with a confirmation of successful flashing.

Addressing Potential Issues

  • Update Failures: Recheck your connections and ensure your receiver is properly in boot mode if the update doesn't succeed.
  • COM Port Detection: Confirm the correct COM port is chosen in the configurator. If it's missing, try reconnecting the dongle and checking the driver installation.

Concluding Thoughts

Utilizing an FTDI programmer like the Radiomaster USB UART Flasher to update ExpressLRS receivers is a valuable strategy when facing issues with more common methods. This tutorial outlines a direct process for restoring and enhancing your ELRS RX, potentially rescuing devices from being written off. Verifying connections and settings before proceeding is vital for a smooth update process. By adhering to these instructions, you're ensuring your ExpressLRS receivers maintain up-to-date firmware, enhancing your FPV flying experience.

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