When upgrading ELRS receivers, there are primarily two options: Wi-Fi and Serial Port. While Wi-Fi upgrading is very user-friendly and doesn't require additional accessories, it can be susceptible to failures caused by unstable networks.
For a more reliable and professional upgrade experience, RadioMaster ExpressLRS UART Flasher is your solution. This dongle is designed specifically for ELRS receiver serial port upgrades, providing a dependable and professional solution for flashing or recovering receivers with a bad flash.
Using 2.54mm pin output and spring-loaded pin adapter or Test hook adapters:
Using regular 2.54mm pin output (Servo plugs):
Please note: The second channel is repurposed as a serial TX, connected to the RX port of the serial port tool. The third channel is repurposed as RX, connected to the TX port of the serial port tool.
Firmware upgraded by RM-CRSF interface output:
Please note: The above receivers can be connected to the receiver's CRSF port by using a 4-wire CRSF cable.
1. Connect the Serial Port Cable with receiver
2. Press the receiver's BOOT button, and insert the serial port tool into your computer
3. Follow the ELRS upgrade tool's instructions to complete the upgrade