BBB doesn't start with a USB Serial cable plugged to the USB Host

Hi everybody,

I have a BBB with a USB Serial plugged to the USB Host (P3). I’m using a 5V power supply connected on P1.

If I disconnect the power supply with the USB Serial still plugged, and connect again, the BBB doesn’t init (the power led does not turn on).

If I unplug the USB Serial, connect the power supply and then plug the USB Serial, everything works.

I tested with 3 different 5V power supplies (1A, 2A and 2,5A), and the result is the same.

Does anybody had the same problem? I looked the schematic and didn’t see anything that prevent the board to start.


Make sure the PC/Laptop/Whatever has the same ground connection as the DC power supply.


Yes, it’s via pin 5 of the serial connector.