Quick Answer
Updating ExpressLRS firmware keeps your radio link reliable and unlocks new features. Use the free ELRS Configurator app to flash both your TX module and receivers over USB or Wi-Fi. The whole process takes about five minutes per device.
For more background on the protocol itself, see our complete ELRS explainer. And if you want telemetry working after your update, our ELRS telemetry guide covers the setup.
Why ELRS Firmware Updates Matter
We flash a lot of ELRS gear in our workshop, and firmware updates are the single biggest factor in link stability. ExpressLRS moves fast. Version 4.x introduced a new binding protocol and improved dynamic power, and the project ships new releases every few weeks. Running outdated firmware means missing bug fixes, worse range, and incompatibility with newer receivers.
The most common issue we see in support tickets is mismatched major versions. A v3 TX trying to talk to a v4 receiver will partially bind then drop mid-flight. Version 4.0 broke backwards compatibility with v3, so everything needs to be on the same major version.
What You Need Before Updating
Download the ELRS Configurator for your operating system (Windows, macOS, or Linux). You need a USB data cable for your TX module or radio, and either USB or Wi-Fi for your receiver. Use a proper data cable, not a charge-only one. This catches people out regularly.
Check your current version via the ELRS Lua script on your radio. If the major version differs between TX and RX (for example, TX is 3.5 and RX is 4.2), update the older one first. Because v4 broke compatibility with v3, moving from v3 to v4 means updating both devices at the same time.
Browse our full range of radio receivers and radio controllers and receivers for compatible hardware.
Updating Your TX Module
Plug your TX module into your radio's module bay or connect via USB. Open ELRS Configurator and select your device category. The Configurator auto-detects the hardware.
Select the latest stable release from the dropdown, pick your regulatory domain (EU 868MHz or FCC 915MHz if using 900MHz gear, though most UK pilots run 2.4GHz), and click "Flash." The process takes about 30 seconds. Our go-to module in the shop is the BetaFPV ELRS Nano TX Module, which flashes cleanly every time.
For internal radio modules like those in the RadioMaster TX16S, use the radio's USB connection directly. The Configurator treats it the same way.
Updating Your Receiver
There are three methods:
Via Wi-Fi (Easiest)
Hold the bind button for 10 seconds. The receiver creates a Wi-Fi hotspot called "ExpressLRS RX." Connect your phone or laptop, open 10.0.0.1 in a browser, and upload the firmware. This works on any ESP-based receiver like the SpeedyBee Nano ELRS Receiver or the GEPRC ELRS Nano Dual Diversity Receiver.
Via Betaflight Passthrough
Connect your flight controller via USB. In ELRS Configurator, select "Betaflight Passthrough." This is the method we use most in the workshop because the FC is usually easier to reach than the receiver.
Via UART (Direct Serial)
Solder a serial adapter to the receiver's TX/RX pads. Only needed if Wi-Fi mode and passthrough both fail. We have rescued bricked receivers this way.
Common Update Problems
Configurator will not detect the device: Try a different USB cable. About half the "my device is broken" support queries we get are resolved by switching to a known data cable.
Receiver will not enter Wi-Fi mode: Double-check that the receiver has power (LED should be on). Some AIO boards need the flight controller powered too. Try Betaflight passthrough instead.
Binding fails after update: Re-bind both devices. Press the bind button on the TX module, then power cycle the receiver. They should link within five seconds.
Lua script shows wrong version: Update the Lua script on your radio SD card. Download the latest from the ExpressLRS GitHub and replace the existing ELRSV3 folder.
FAQ
Q: How often should I update ELRS firmware?
A: Update when a new stable release ships, which is roughly every 4 to 6 weeks. You do not need to chase nightly builds. If your link is working well, there is no urgency, but do keep both TX and RX on the same major version.
Q: Can I mix different ELRS versions on TX and RX?
A: Within the same major version (3.x with 3.x, or 4.x with 4.x), yes. Mixing major versions causes binding issues. V4 specifically broke compatibility with v3, so a v4 TX will not talk to a v3 RX. Always match the major version.
Q: Do I need to re-bind after updating?
A: Usually not within the same major version. Across major version changes (especially v3 to v4), re-binding is required. It takes five seconds, so we re-bind after every update as a habit.
Q: Will updating erase my receiver settings?
A: Wi-Fi updates preserve your settings. Passthrough and UART flashes reset to defaults. Note down your binding phrase before flashing.