Who this is for
FlyingRC flight controller users who need to recover, replace, or update STM32-based firmware from a local file.
Before you start
- A FlyingRC STM32-based board and its matching firmware file from the Downloads page.
- ST STM32CubeProgrammer installed on your computer.
- A known-good USB data cable. Charge-only cables will not expose the bootloader.
- Propellers removed and external power disconnected unless the product manual explicitly requires it.
Check before connecting
- Match the firmware target to the exact board model and hardware revision before writing. A wrong target can leave the board unable to boot normally.
- Follow the product manual if its BOOT / DFU entry method differs from this general workflow.
- Do not connect motors, propellers, or live payload wiring while testing firmware recovery.
Steps
Download the correct firmware
Open the FlyingRC Downloads page, choose your exact product, and download the .hex firmware that matches the listed firmware target and board revision. Keep the checksum file nearby when available.
Prepare the board safely
Remove propellers, disconnect battery power, unplug unnecessary peripherals, and use only USB unless the product manual says otherwise.
Enter the STM32 bootloader / DFU mode
Hold the board BOOT button or BOOT pads as described in the product manual, then plug in USB. The board should enumerate as an STM32 bootloader / DFU device.
Connect in STM32CubeProgrammer
Open STM32CubeProgrammer, choose the USB connection mode, select the detected DFU device, then click Connect. If no USB device appears, re-enter bootloader mode and try another USB cable or port.
Load and program the .hex file
Open the Erasing & Programming view, select the downloaded .hex file, keep verification enabled, then start programming. Do not unplug USB until STM32CubeProgrammer reports success.
Reboot and confirm normal firmware startup
Disconnect from STM32CubeProgrammer, unplug USB, then reconnect normally without holding BOOT. Open the matching configurator or ground-station software and verify that the firmware connects.
Troubleshooting
STM32CubeProgrammer does not show a USB device
Use a data cable, try another USB port, hold BOOT before plugging in USB, and check whether the product manual requires a specific bootloader entry method.
Programming starts but fails
Reconnect in DFU mode, enable verification, avoid USB hubs, and confirm the file is a complete FlyingRC .hex firmware file rather than a compressed package.
The board still starts old firmware
Confirm the programming operation completed successfully, then power-cycle the board without holding BOOT. If needed, repeat the write with the correct .hex file selected.
Configurator cannot connect after flashing
Use the configurator that matches the firmware family, check the expected USB serial device, and verify that the board was flashed with the correct target.