Tx Backpack Setup
Preparing the TX Module for Backpack Firmware Flashing¶
For the Happymodel TX Modules, you will need to move the jumpers or DIP switches into the correct position before flashing the firmware. Please see the USB/UART Flashing section of your particular TX Module for the jumper or DIP switch position.
You need to activate the
Backpack Flashing jumper or DIP switch (middle pair). Opening up the module enclosure will be needed as well to access the Buttons on the modules. Make sure your computer recognizes your TX module as a
USB to UART Bridge. Windows drivers are linked in the Flashing Guides.
For the NamimnoRC Flash and Voyager TX Modules without an OLED screen (Gen 1 STM-based), make sure you're able to access the Backpack Web Update page (see Flashing Guide) via WiFi.
NamimnoRC OLED-equipped TX Modules and AxisFlying Thor modules should come preflashed with Backpack firmware.
Backpack Firmware Flashing¶
Flashing Backpack firmware is supported by the ExpressLRS Configurator since v1.2.0.
HappyModel TX Backpack
AXIS THOR TX Backpack
FrSky TX Backpack
Namimno Non-OLED TX Backpack
Namimno Flash OLED TX Backpack
Flashing via USB/UART¶
For the Happymodel TX modules, connect to your computer via USB. As stated above, the module should be detected as a
USB to UART Bridge and the jumper/DIP switches are set in the correct position (middle pins/switches should be On).
In ExpressLRS Configurator, select the appropriate Target and enter your binding phrase which will be used to bind the Backpacks together. It can be different from your usual binding phrase, but there's no issue if you want to use the same. You can also set your Home WiFi Network SSID and Password (version 0.2.0 or newer) to enable updating over your home WiFi.
Once set, click Build and Flash on the ExpressLRS Configurator.
Button Dance: A few buttons are needed to be pressed on the module while the firmware is compiling. Press and Hold the
GPI0 button then the
RST button (GPIO is still pressed) then release the
RST button and then the
If you did things right, a
Success message should appear.
Unplug the USB and change the position of the jumpers/DIP switches for the
Normal Operation (refer back to the module's Flashing Guide page for the correct position).
Put back the cover of the module and attach it to your module bay.
Flashing via Passthrough¶
Radiomaster Ranger Series
These devices use the base
HappyModel TX Backpack as a target.
- Plug in a USB Data Cable into the module.
- Select the latest Backpack Release version.
- Select the device target,
HappyModel TX Backpack.
- Select the
via Passthroughflashing method.
- Set your runtime options.
Build and Flash
- Wait for the process to complete.
Flashing via WiFi (ESP-based TX Modules)¶
The following section applies to more recently released TX modules like the NamimnoRC OLED-equipped Modules. If you have the older Happymodel modules and have updated their backpack firmwares to at least 0.1.0, then this can be used for future updates.
Using the ExpressLRS v2.0 Lua script, navigate to
WiFi Connectivity and select
Enable Backpack WiFi. The Backpack WiFi Access Point will immediately activate. Connect to the
ExpressLRS TX Backpack AP (password is
expresslrs). Navigate your browser to http://10.0.0.1/.
Build the TX firmware using the ExpressLRS Configurator. Grab the built
firmware.bin and drag-and-drop it into the File Upload section of the webpage and click Update. Wait a bit (~10s) for the "Update Success! Rebooting...". The AP should automatically disappear and disconnect.
Flashing via WiFi (NamimnoRC Gen1 TX Modules)¶
For the First Generation NamimnoRC TX modules (No OLED), you will have to first Build the Backpack firmware. Once built, grab the
backpack.bin file from the folder that the ExpressLRS Configurator opened. Open the URL http://elrs_tx.local on your browser and scroll down to where the WiFi Backpack Firmware Update section is (shown in the image below). If the page isn't loading, make sure you have followed the Wifi Flashing guide for these modules (see Flashing Guide).
Wait for a bit (~10s) after the message "Update Success! Rebooting..." appears before you power-cycle the module. Your TX Backpack should now be ready.
Flashing via ETX Passthrough¶
RadioMaster Zorro TX Backpack
RadioMaster TX16S Backpack
RadioMaster TX12 Backpack
RadioMaster Boxer Backpack
This method is the result of the collaborative effort between EdgeTX, RadioMaster, and ExpressLRS.
With your handset turned on, connect a USB data cable to the USB data port of the Radio. Select
USB Serial(Debug) or
USB Serial(VCP) in the options window that pops up.
Using the ExpressLRS Configurator, select the appropriate version and the correct Device Target and set the Flashing method to
Set your Binding Phrase and your Home WiFi SSID and Password (Optional).
Click Build and Flash on the ExpressLRS Configurator.
Wait for the process to complete and you should see the green
Unplug the USB from the handset and you're set!
Starting in 0.2.0, you can Update via your Home WiFi Network¶
With your Home Network SSID and Password set, when you activate the WiFi mode via the Lua script (
WiFi Connectivity ->
Enabled Backpack WiFi), the Backpack will try to connect to your Home WiFi Network. Once connected, you can access the Web Update page via http://elrs_txbp.local/ and upload your firmware there.
The ExpressLRS Configurator will also detect the device after it has been connected. It will be listed in the "Device List" section, and you can press
SELECT, so that the correct target is automatically selected for Build.
Alternatively, you can also Build and Flash via the Configurator through WiFi without having to access the Web Update page (just like any ESP-based ExpressLRS receiver).
How to check you have updated the TX Backpack Firmware?¶
Make sure you set the jumpers or DIP switches on your modules (if required, e.g. the Happymodel TX Modules) to the
Normal Operation position (refer to the top of this page). This allows the main ESP32 chip to talk to the Backpack chip. The Backpack will NOT work properly if the DIP switches or jumper pins are not in the
Normal Operation position.
Change the position of the DIP switches or jumper pins to
Normal Operation if required for your module (e.g. Happymodel TX modules).
Navigate to the
WiFi Connectivity folder of the ExpressLRS v2 Lua script and select
Enable Backpack WiFi. Scan for Access Points, and ExpressLRS TX Backpack should appear. Connect to it and point your browser to http://10.0.0.1/.
If you have set your Home Network SSID and Password, point your browser to http://elrs_txbp.local/.
The main banner will show you what kind of device it is and the firmware version that's flashed into it.
Setup your VRx Backpack¶
Proceed to the VRx Backpack Setup section to setup your VRx Backpack, if desired.
The Backpack Usage section provides further details on ExpressLRS Backpack Operation, including Binding, LED Status codes, and more.