How to Flash ExpressLRS V3 to Happymodel Mobula6 Mobula7 Mobeetle

If your Mobula6, Mobula7 and Mobeetle has a flight controller with built-in SPI ExpressLRS receiver, here is how you can update its firmware from ELRS 2.X to ELRS 3.X. All you need is to update the firmware on the flight controller.

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I just updated my Mobula 7 and Mobeetle to ExpressLRS V3 and thought I should document my steps.

Before updating Betaflight, make sure your Mobula6/Mobula7/Mobeelte has this FC: CRAZYBEEF4SX1280, which has a built-in SPI ELRS receiver. The flight controller comes with Betaflight 4.3.0 firmware which only supports ELRS 2.X. When you update your ELRS TX module to 3.X firmware, it will no longer bind with your quad, therefore you have to update your quad’s receiver to ELRS 3.X version as well if you want them to work. Anyway I recommend updating all your ELRS hardware to V3 firmware just for the latest features and bug fixes. Now, in order to update the ELRS firmware on your whoop’s SPI receiver, you have to update Betaflight because it’s part of the Betaflight firmware code (just how SPI receiver works).

Backup Betaflight

Before proceeding, make sure to back up your Betaflight settings: How to Backup / Restore Betaflight Configuration. If you want the factory default, here it is: https://intofpv.com/t-cli-dump-for-happymodel-mobeetle

You can apply your settings after updating Betaflight so you don’t have to set it all up again.

If you want to restore your whoop back to its original state, simply flash the original Betaflight firmware version (i.e. 4.3.0), and load your backed up preset in the Presets tab.

Update Betaflight Firmware

If you’ve never flashed Betaflight before, here’s a tutorial: How to Flash/Update Betaflight on Flight Controller.

ELRS V3 support will come in Betaflight 4.4, but the stable release is not yet here, so we will have to download a custom firmware which supports ELRS V3 (it’s only 4.3.1 version, but it’s been tested more than the 4.4 RC, that’s why I prefer to use it even though it’s older): https://www.happymodel.cn/index.php/2022/09/26/crazybeef4sx1280-4-4-0-support-expresslrs-v3-0-beta-version-firmware-download/

In Betaflight Configurator -> Firmware Flasher, press the button “Load Firmware (Local)”, and choose the firmware you just downloaded. Then flash it.

When applying preset, you will get an error about Simplified Gyro Lowpass Filter value, just ignore it and click save anyway. When you are done, go to the PID tab, Filter, and disable both Gyro Lowpass 1 and 2.

How to Bind?

Two ways to bind your whoop, enter a bind phrase, or press the bind button in the receiver tab.

Enter Bind Phrase

Enter your bind phrase on this page, it will generate a code for you to enter in CLI: https://www.expresslrs.org/2.0/hardware/spi-receivers/#uid-byte-generator

In CLI enter the code in this format:

set expresslrs_uid = 212,50,59,163,20,74 save

Bind Button

Under the Receiver tab in the Betaflight Configurator, there’s a Bind Receiver button, click that the quad will enter Bind mode. Now if you click the “Bind” option the ExpressLRS LUA script in your radio, they should be bound within seconds.