I have a DuetWiFi and needed to flash a new, custom firmware onto it. At first, the device was connected to the PC, but after erasing the memory to flash a new firmware using the BOSSA flash, it is no longer identified by my computer as a USB device or COM port.
The board has the 3.3V, 5V, diagnostic, and one more blue LED on. Repeated attempts at erasing, resetting, and reconnecting have not worked.