how to flash a .bin or a .hex

Im trying to turn one of my longan nano as a rv-link jtag interface.
Im not successfull to have it compiled with plateformio but it is possible to download two files for nano : a .bin file and a .hex file
But doesnt seems to work well neither:
sudo dfu-util -a 0 -s 0x08000000:leave -D ~/Downloads/longan-nano\ gd32vf103.hex
flash it, but then nothing happens at all when i replug the board with usbC. not even a little /dec/ttyACM0 appears.

What am i doing wrong ?