Sorry I have not responded immediately - I have not got the email notification somehow.
If the help screen of
dfu-programmer is shown to you after issuing
launch then you might have old
This command has been renamed in 0.7 version, while in 0.6 it was called
start. This should be added to the guide (@nitroalex).
I wonder why the device is not visible to you, even with
sudo. The update process is usually straightforward on Ubuntu. If you would find yourself once again in this situation please attach results of
lsusb command as well.
Lesson learned from this is making own update application, which would collect system details and suggest possible solutions to the connection issue.
Just for completeness (for others reading this topic) - linking your working update guide for Windows 10: