Netduino3wifi cannot run

i had updated netduino3wifi from 4_3_2_1 to 4_3_2_2and conected the wifi with NetduinoDeploy an it run good, but something happen lead to the board cannot enter the DFU mode or Bootloader, that is the NetduinoUpdate and the NetduinoDeploy unable to obtain the message from the netduino3wifi board, so i try to use the st dfuse_demo flash the board ,then is also can not obtain the message, start above three exe file is the same result. so i doubt the stm32f427 is locked or damage, but i can still assembly a new program to the board and it run well, but the wifi cannot be set because the NetduinoUpdate and the NetduinoDeploy cannot set the board no longer. so here i hope someone know the situation problem give me adivce or suggest,thank you !
in addition if the stm32f427 is damaged, can i buy a new stm32f427 and weld to the board, and then it canbe flash or update?

and now i connect the board to the computer with usb line ,the board pwr and led bright a time then extinguish. is damage?

now i weld a new stm32f427 cost 30 rmb onto the board and it run normal and well again. so i think the problem is i had run >5v to the point of the board and it damage.