Updating Firmware on RadioMaster RP Receiver
If you flash directly to version 3.x, and encounter a "Not Enough Space" popup during WiFi flashing, first flash the receiver to version 2.5.2, then flash to version 3.x.
If the receiver firmware is already version 3.x, and you still encounter a "Not Enough Space" error when flashing via WiFi, ensure you have selected the correct flashing method in the configurator (in this case, via WiFi). Please follow the steps listed below.
You can also update directly to version 3.x through Passthrough or UART.
I. Connecting the Receiver
It should be noted that the RX pin on the receiver should be soldered to the TX pad on the flight controller board, and the TX pin on the receiver should be soldered to the RX pad on the flight controller board.
RadioMaster RP1 2.4GHz:

RadioMaster RP2 2.4GHz:

RadioMaster RP3 2.4GHz:

II. Configuring the Flight Controller
To properly configure your flight controller, the following settings apply to INAV, Betaflight, and other flight controller software.
If any of these settings are incorrect, the following steps will not proceed smoothly, and you may encounter issues later.
- After completing the configuration of your flight controller software, close its configurator and unplug/replug the flight controller's USB cable, or disconnect and reconnect it from the computer to refresh the connection and ensure the port is not occupied.
- If these settings are incorrect, subsequent operations, especially updating via the Passthrough method or the receiver not working properly, will be affected.
3. Updating Receiver Firmware
3.1 Method 1: Via Passthrough
- Ensure you have properly connected the receiver and configured your flight controller.
Important
This is an important step to ensure a successful update. If you have not completed these operations, please go back.
Connect the receiver to the flight controller board and connect it to the computer via a USB data cable.
Launch ExpressLRS Configurator on your computer, ensure the Official Releases tab is active, and select the Released version to flash to the RX module.

- Select the Device Category and Device target that match your hardware.
Device Category: RadioMaster 2.4 GHz
Device: RadioMaster RP1 2.4GHz RX
- RadioMaster RP2 2.4GHz RX
- RadioMaster RP3 Diversity 2.4GHz RX

- Set the Flashing Method to BetaflightPassthrough

- Set the firmware options for the device.
- Regulatory Domain (Required, select the domain suitable for your location or country/region where you will be flying)
- Binding Phrase (Optional but highly recommended. Note this phrase as it should be the same on your other devices, otherwise they will not bind or sync)
- Local WiFi Network Credentials (Optional. Will be used when the device enters WiFi mode next time).

- Click the Flash button.

- Wait for the process to complete. A green success bar will appear in ExpressLRS Configurator.

- After a few seconds, the LED on the receiver should return to slow-blink LED mode.

3.2 Method 2: Via UART
- Connect the receiver to a UART adapter. You need to disconnect the receiver from the flight controller and connect it to the UART/FTDI adapter as shown below.

If your receiver has Boot pads instead of a Boot button, solder the Boot pads together or ground them. If your receiver has a boot button, find it and press it.
Insert the UART adapter into a USB port on your computer.
- The LED on the receiver should be solid on. If it is blinking rapidly, repeat the previous step.
- After the LED on the receiver is solid on, release/unpress the button on the receiver (if any).
Drivers need to be installed when using the UART adapter for the first time. Common USB to UART adapter chips include: CP210x, FTDI FT232, CH340 and CH9102 (links to driver download pages).
Go to your computer's Device Manager to check if the UART adapter is properly detected as a USB to UART device.

- Launch ExpressLRS Configurator on your computer, ensure the Official Releases tab is active, and select the Released version to flash to the RX module.

- Select the Device Category and Device target that match your hardware.
Device Category: RadioMaster 2.4 GHz
Device: RadioMaster RP1 2.4GHz RX
- RadioMaster RP2 2.4GHz RX
- RadioMaster RP3 Diversity 2.4GHz RX

- Set the Flashing Method to UART

- Set the firmware options for the device.
- Regulatory Domain (Required, select the domain suitable for your location or country/region where you will be flying)
- Binding Phrase (Optional but highly recommended. Note this phrase as it should be the same on your other devices, otherwise they will not bind or sync)
- Local WiFi Network Credentials (Optional. Will be used when the device enters WiFi mode next time).

- Click the Flash button.

- Wait for the process to complete. A green success bar will appear in ExpressLRS Configurator.

- After a few seconds, the LED on the receiver should return to slow-blink LED mode.

3.3 Method 3: Via WiFi
3.3.1 Method 1: Manual Upload via Local WiFi
Important
This method is only available if you have previously flashed or configured the TX module to use your home WiFi SSID and password, and the module is able to successfully connect to that WiFi network.
- Insert the receiver into the flight controller and power the flight controller using a data cable. Launch ExpressLRS Configurator on your computer, ensure the Official Releases tab is active, and select the Released version to flash to the TX module.

- Select the Device Category and Device target that match your hardware.
Device Category: RadioMaster 2.4 GHz
Device: RadioMaster RP1 2.4GHz RX
- RadioMaster RP2 2.4GHz RX
- RadioMaster RP3 Diversity 2.4GHz RX

- Set the Flashing Method to WiFi

- Set the firmware options for the device.
- Regulatory Domain (Required, select the domain suitable for your location or country/region where you will be flying)
- Binding Phrase (Optional but highly recommended. Note this phrase as it should be the same on your other devices, otherwise they will not bind or sync)
- Local WiFi Network Credentials (Optional. Will be used when the device enters WiFi mode next time).

- Click the Build button.

- After the build process is complete, a Temp folder window should pop up.
- Do not close this Temp folder as this is where you will get the firmware file for the next steps.
- If you plan to upload the firmware file later using a phone or tablet, copy the firmware file to your device.
Important
With the release of ExpressLRS 3.3.0 and ExpressLRS Configurator 1.6.0, only one file firmware.bin will be displayed, use this file for the next steps.

- Put your receiver into WiFi mode.
Method 1: Using Auto WiFi Mode
Connect the receiver to the flight controller board, then power the flight controller.
Wait for at least 60 seconds or long press the BAT key on the receiver for 5 seconds, the LED will change to rapid blinking mode or green breathing LED mode (for receivers with RGB LED), indicating it is now in WiFi mode.
- The Auto WiFi On Interval setting controls how long the device waits to enter WiFi mode after power-on and without receiving valid CRSF packets.

Method 2: Using ExpressLRS Lua Script
The receiver must be bound to the transmitter, for detailed steps please refer to: https://docs.corewing.com/plane/ardupilot/settings/rc/elrs-bind.html
- Press the SYS key on the transmitter, the radio will display the tools menu where you can find the Lua script.
- Older radios or radios with only one menu button must long press the Menu button to access the System Menu.
- Please refer to your Radio user manual for instructions on how to access the system menu.

- Press Enter to load it, scroll down and select WiFi Connectivity

- Select and press Enable RX WiFi

- The receiver LED will change to rapid blinking mode or green breathing LED mode (for receivers with RGB LED), indicating it is now in WiFi mode.

- When the receiver is in WiFi mode, turn on WiFi on your computer → connect your computer to the ExpressLRS RX receiver WiFi, the default password is lowercase "expresslrs".

- After connecting to WiFi, wait 10 seconds and a browser will automatically open and redirect to the 10.0.0.1 page; if the browser does not open automatically, you can directly enter 10.0.0.1 in the browser address bar to access the receiver.

- Go to the UPDATE page, click "SELECT FIRMWARE FILE" to load the file. In the pop-up window, select the downloaded firmware archive, and the webpage will automatically start flashing the firmware.

- Until the following pop-up appears on the webpage, indicating the receiver firmware has been successfully flashed.

- After a few seconds, the LED on the receiver should return to slow-blink mode.

3.3.2 Method 2: Auto Upload
Put the receiver into WiFi mode, for detailed steps please refer to point 7 above.
Insert the receiver into the flight controller and power the flight controller using a data cable. Launch ExpressLRS Configurator on your computer, ensure the Official Releases tab is active, and select the Released version to flash to the TX module.

- Select the Device Category and Device target that match your hardware.
Device Category: RadioMaster 2.4 GHz
Device: RadioMaster RP1 2.4GHz RX
- RadioMaster RP2 2.4GHz RX
- RadioMaster RP3 Diversity 2.4GHz RX

- Set the Flashing Method to WiFi

- Set the firmware options for the device.
- Regulatory Domain (Required, select the domain suitable for your location or country/region where you will be flying)
- Binding Phrase (Optional but highly recommended. Note this phrase as it should be the same on your other devices, otherwise they will not bind or sync)
- Local WiFi Network Credentials (Optional. Will be used when the device enters WiFi mode next time).

- Click the Flash button.

- Wait for the upload to complete. A green success bar will appear in ExpressLRS Configurator.

- After a few seconds, the LED on the receiver should return to slow-blink mode.

———— This article is referenced from ExpressLRS Getting Started: https://www.expresslrs.org/quick-start/receivers/axisflying-thor/