I recently upgraded my MacBook Pro to Mojave. Now I'm not able to connect to my Arduino board with ch340g usb-to-serial chip. It is a Arduino board with AtMega 328 and ESP8266 integrated. I downloaded the drivers from the Chinese website for the ch340 and also removed old installations, like some tutorials tell me. I just can't get a /dev/cu.* port (besides the /dev/cu.Bluetooth-Incoming-Port.

I do have an external FTDI usb to serial board. I didn't get to it to try to connect it.

Does someone know how to get the ch340 to work on MacOS Mojave, or as a last resort: use the FTDI to program/monitor the Arduino board?

2 Answers 2


Ok, this is the solution for me:

remove all old drivers:

sudo rm -rf /Library/Extensions/usbserial.kext
sudo rm -rf /System/Library/Extensions/usb.kext

Now reboot the computer.

And then (very important, because it took me 10 cables to find the right one) use a fully connected cable ;-)

Now I have these ports:

  • 1
    Sven's answer is 100% correct the fully connected cable is what hung me up for a few hours. Took 6 cables to find the right one.
    – kave
    Dec 22, 2018 at 4:36
  • 1
    What do you mean with "fully connected cable"? Is this a specific kind o USB cable or what? Jun 3, 2019 at 1:05
  • 3
    It is a USB cable with also the data lines connected. Most cables you get with phones and devices just have the +5 and GND connected so they don't pass data.
    – Sven
    Jun 3, 2019 at 7:30

this my problem too. i found these solutions

  1. mac-usb-serial app
  2. a topic in arduino forum

make sure delete old usb driver in these path

then install it again download link

  • 1
    When I experienced this problem, installing the latest driver still failed, but when I removed the old drivers and did not install anything new, it worked fine. Nov 2, 2018 at 16:01

Not the answer you're looking for? Browse other questions tagged or ask your own question.