Flashing MicoAir743v2 from Betaflight to PX4

This doc walks you through a safe way to re-flash the MicoAir743v2 flight controller between PX4 and Betaflight via DFU/bootloader.
How to flash from PX4 to Betaflight

This guide is ONLY for the MicoAir743v2 flight controller.
If you’ve got a Pixracer / COEX Pix / Pixhawk, use the Pixracer PX4 flashing guide instead:
PX4 firmware on Pixracer

_{MicoAir743v2 flight controller}

Contents

1. Software & firmware links
2. Entering DFU / bootloader mode
3. Flashing Betaflight to PX4

Software & firmware links

• QGroundControl (QGC) (official releases): github.com/mavlink/qgroundcontrol/releases
• STM32CubeProgrammer (Google Drive): drive.google.com (STM32CubeProgrammer)
• PX4 firmware for MicoAir743v2: drive.google.com (PX4 firmware)
• PX4 bootloader for MicoAir743v2: drive.google.com (PX4 bootloader)

Entering DFU / bootloader mode

1. Hold the BOOT button on the FC.
2. While holding BOOT, plug the USB cable into your PC.
3. Your system should detect it as DFU / STM32 Bootloader.

Flashing Betaflight to PX4

Programmer setup (STM32CubeProgrammer)
Before flashing, download and install STM32CubeProgrammer.

1. Put the flight controller into DFU (hold BOOT and plug it in via USB). Open STM32CubeProgrammer and click the connection protocol selector (UART).

   

2. Select the USB protocol.

   

3. Refresh ports (click the button to the right of the port selector). It should auto-pick the right one.
   If it doesn’t, the FC is not in DFU mode — redo step 1.

   

4. Click "Connect".

   

5. Do a full wipe: click the eraser icon in the bottom-left, confirm in the popup, and wait until it’s done.

   

6. Click Open file and select MicoAir743v2_PX4-1.15.x_bootloader.bin.

   

7. Click "Download" to flash the bootloader and wait until it finishes.

   

8. Click "Disconnect".

   

9. Exit or close STM32CubeProgrammer.

   

10. Open QGroundControl and click the logo in the top-left corner.

    

11. In the popup menu, select "Vehicle Configuration".

    

12. Click "Firmware", then reconnect the flight controller without holding the BOOT button.

    

13. In the "Firmware Setup" screen, enable "Advanced settings".

    

14. In the list at the bottom, select "Custom firmware file..." and click OK.

    

15. Wait for flashing to finish.

    

16. You can now move on to configuring the flight controller.