Can not connect to my Extension Board/Lopy4

[pierrot10]

Hello
I am trying to upload code into my LoPy4 via the expention board. I could it until I lost connection.

I reconnect the USB cable and look at More->Get Serial Port

The only thing I can see it

/dev/cu.iPhonedePierrot-Wireles (copied to clipboard)
Connecting on /dev/cu.usbserial-DQ00DAHG...

But it can not see my USB port.

What can I do?
I rember, we could reset the board? Isn't?

Thank

[robert-hh]

@pierrot10 which model of the expansion board arte you using. Version 2 (one push button) or version 3 (two push buttons). Version 2 is more simple. If you cannot see the serial port, it is a problem of the physical connection (cable, jumpers on the board) or the OS X driver. Version 3 adds to the list of trouble sources the firmware in the PIC controller on the board.
I assume that you also do not get a REPL prompt.