How can I upload SoftRf to T-Impulse?

[ulrichard]

I am trying to flash SoftRf to the T-Impulse.
With the information I found so far, I thought this would be the command:
dfu-util -a 0 -s 0x08000000 -R -D ~/Downloads/SoftRF-firmware-v1.4-S76G.bin
It seems to upload successfully, but after that, the display stays empty. At least, I can repeat the process, which means the device is not bricked.
What would be the correct command to use? The documentation is a bit sparse on that device.