Hello,
I'm happy because almost one year after being stopped by a (finally small) problem, it is solved.
First board (Duet 2 wifi v1.04 #918.1217) ordered via RepRapWorld in Feb2019, managed to configure it, make small movements, but quickly no motors were moving, the 5V was not converted from the 12V, but if supplied via USB I could at least heat the bed... I thought it was related to a too quick manual move as the Z stage collapsed at some point (and generated too much current was my guess). It seemed related to a fuse, I feared to have to change a surface mounted part (size 0603). Bought a second board (#419.0544 v1.04b) as a replacement in June 2019 but left the project here.
Today I finally check everything again, update the firmware on the first board just in case, and establish the same diagnostic : I have to provide 5V by USB and only can heat the bed, nothing else move.
I open the second board, update the firmwares, and as I was about to swap them, I look how everything is wired and it became clear (but strange) : the blade-fuses were inverted in the first board ! This is confirmed by reading the documentation.
Buying spare fuse for later, and using the 1A of the second board for now.
Will be back with a kinematic problem soon, as I have a "scissor" Z to get working