Board support package for the Adafruit feather f405 with some abstractions and helpers for the onboard peripherals.
Support and examples for the - onboard led - Neopixel led - SD-card reader - Spi flash
dfu-util -a 0 --dfuse-address 0x08000000 -D firmware.bin
Or look at dfu-flash.sh for a complete example
You will have to solder leads to the programming pads on the back of then board. Then you can use a programmer like a ST-link v2 and flash and debug the board with Probe or Openocd.
cargo embed --release example neopixel
https://learn.adafruit.com/adafruit-stm32f405-feather-express/dfu-bootloader-details