@markxu said in Duet 2 Wifi won't on.:
What could be the problem with my board?
If it works from USB it could be the black square chip labeled U3 has failed, take a close look at it, About 2cm in from the fuse between Vin and Bed output.
and in general https://duet3d.dozuki.com/Wiki/What_to_do_if_your_Duet_won't_respond