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.

Check out all our ExpressLRS Products, Receivers, and the rest of our RadioMaster Products! 

Compatible Receivers

Using 2.54mm pin output and spring-loaded pin adapter or Test hook adapters:

• All RP SERIES ELRS RECEIVERS

Using regular 2.54mm pin output (Servo plugs):

• ER3C-i 2.4GHz ELRS PWM Receiver
• ER5C-i 2.4GHz ELRS PWM Receiver
• ER4 2.4GHz ELRS PWM Receiver
• ER5A 2.4GHz PWM Receiver
• ER5A V2 2.4GHz PWM Receiver
• ER5C 2.4GHz PWM Receiver
• ER5C V2 2.4GHz PWM Receiver
• ER6G & ER6GV ELRS PWM Receiver

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:

• ER6 2.4GHz ELRS PWM Receiver
• ER8 2.4GHz ELRS PWM Receiver
• ER8G & ER8GV ELRS PWM Receiver

Please note: The above receivers can be connected to the receiver's CRSF port by using a 4-wire CRSF cable. 

How to upgrade firmware

• 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

Download the USB to UART Driver here.

Features:

• Based on the Revolutionary ExpressLRS System
• High performance, high reliability, flexible configuration, fast response speed and ultra-long range
• Support 8 PWM Channels
• Optimized ground up PCB design
• Automatically voltage telemetry of external battery voltage or built-in receiver voltage
• Supports Wi-Fi updates and WEBUI configuration
• High quality 2.54 mm connector
• Standard 20 cm High Sensitivity Antenna
• Reserve 4pin CRSF input port
• Shell adopts one-piece molding process with high structural strength
• For fixed-wing aircraft and more

 Specifications:

• Item: ER8 2.4GHz ELRS PWM Receiver
• Power supply: DC 4.5 - 8.4V
• Antenna type: 20cm high sensitivity antenna
• Wireless protocol: ExpressLRS 3.2 pre-installed
• Output channel: 8CH PWM
• Telemetry power: maximum 100mw (LUA Adjustable)
• Battery voltage detection range: DC 4.0 - 35V
• Bus interface: CRSF
• Weight: 16.5 grams
• Size: 43*30*15mm
• Firmware: Device Category: Radiomaster 2.4Ghz / Device: RadioMaster ER8 2400 PWM RX

Size:

Package Includes:

• 1 * RadioMaster ExpressLRS USB Uart Flashing Tool
• 1 * Pogo Probe
• 1 * 1.25mm Serial Port Cable - Type A
• 1 * 2.54mm Serial Port Cable - Type B
• 1 * Serial Port Test Hook - White
• 1 * Serial Port Test Hook - Green
• 1 * Serial Port Test Hook - Red
• 1 * Serial Port Test Hook - Black
• 1 * User Card