@paul-thornton The timing is rather critical. Couldn't you extend the time window for updating to let's say 30s?
Hi @pwest, I've added it to our documentation to avoid further confusion.
@tealbrains & @Xykon : thanks all , that was that ! sudo dfu-util -D ./expansion3_0.0.9.dfu -R -v (I had added my user to dialout group already : not enought)
Thanks for this information. Aparently I misunderstood documentation all those names are confusing at begining.