I have attached photo of the clone Uno board recently acquired, and I am working on a Mac OS X 10.7.5

I have sourced the solution from http://javacolors.blogspot.com/2014/08/dccduino-usb-drivers-ch340-ch341-chipset.html

Which suggests to install 340/341CH drivers and run a sudo code. When I plug in the Uno board, the Arduino IDE still does not show under port selection, the "dev.tty.usbserial"

and as such I cannot contact or upload any command to the Uno board. Been trying for a whole day.. please help if you know a possible solution

This is the board: Uno board

I bought the board from this site:


screenshot from the IDE does now show any usbserial IDE screenshot

  • It looks like the device node for a ch340 on a Mac should be of the form tty.wchusbserial### - at least that is what the screenshot is showing at codenuke.net/2015/01/… – Chris Stratton Feb 21 '15 at 7:41

You will need to allow the use of unverified drivers for this version of the Arduino. Unlike the genuine Arduino this board needs the ch340 and ch341 drivers and because they are not verified you will need to run the following command in order for them to work:

sudo nvram boot-args="kext-dev-mode=1"

I just got a handful of these clones (so cheap) and once I installed the drivers and then set the nvram kernel extensions to dev mode all was OK.


This may be better asked on http://apple.stackexchange.com

At the terminal run ioreg -p IOUSB then plug in the Arduino and see what changed.

On my Mac the setting is serial.port=/dev/tty.usbmodemfa131

  • A genuine UNO with an ATmega16u2 implement USB CDC will have a device node of that form, yes. But that is not what the poster is connecting. They are using something based on a ch340 chip instead. – Chris Stratton Feb 21 '15 at 7:38
  • @ChrisStratton and if the OP posted the ouyput of ioreg -p IOUSB we would know which chip. – Milliways Feb 21 '15 at 9:01

I have a Mac running OSX that is one version older than yours, and had the same problem. Once I installed the CH340 drivers, then plugged in my $3 Arduino, there was a kernel panic and I had to reboot the computer. After trying every "fix" I could find on the internet, I ordered 2 of every popular USB to serial converter on ebay.

The problem is the CH340 drivers do not always work well with OSX. Some folks are lucky and they work great, and other have issues.

A permanent solution is to use a PL2303HX USB to RS232 adapter: http://www.ebay.ca/itm/For-Arduino-Module-Converter-PL2303HX-Converter-NEW-TTL-USB-To-RS232-Adapter-/142004090259?hash=item21101a7593:g:D70AAOSwSWJXRWJV. You will have to download a driver and install it first: http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=229&pcid=41 (Mac OS X Universal Binary Driver v1.5.1).

To use this converter, power up the Arduino using the power jack with 7 - 9 VDC. Connect the PL2303HX ground, TX and RX to the Arduino and plug it into your computer. If a dialog box pops up just cancel it. After you click the upload button in the Arduino IDE, you will see "Binary sketch size.." in the Debug window. Press the reset button on the Arduino for 1/2 a second then release it. The sketch should upload.

The PL2303HX is VERY dependable. Plug it in, look at the Arduino > Tools > Serial Port in the IDE and there it is. Unplug the adapter then recheck the serial port and it's gone. It doesn't matter which USB port you plug it into, the port name is the same for either and should look something like this:

enter image description here

You can even use the PL2303HX with a "stand alone" ATMega328P-PU. Make sure to connect a 10k ohm resistor from 5 VDC to pin 1 and momentarily ground pin 1 when you see "Binary sketch size.." in the Debug window.

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