@t3p3tony Double clicking the reset button turns it into:
On windows: serial port changes to "Serial USB unit (COM4)" and under USB-units there's a "Duet3-Mini5+"
On Linux: a mounted volume named DuetBoot shows up with the 3 files (CURRENT.UF2, INDEX.HTM and INFO_UF2.TXT).
No, can't connect in any way.