Anthony Mallet writes:
| | > But I just can't find how to launch two separate X servers.

Even more simple:

After a fresh reboot, without xdm, launching a single X server on
the second board (the one which isn't used at boot) doesn't work.

Everything looks fine, I can abort with ctrl-alt-backspace and so forth,
but there is no signal at all on the second display (and the first one
switches to vt05). Not a single error message, nowhere (XFree86.*.log) :|