CH340G USB Arduino clones on OSX Yosemite

Recently I picked up a few Arduino clones on eBay and have faced a few issues in getting them to be recognised by Arduino IDE on OS X Yosemite. Here’s a quick guide to getting them running:

Firstly the chips on the boards for USB comms are called CH340G USB and you need to get the drivers in place on OS X, so grab them off this site:

http://www.wch.cn/downloads.php?name=pro&proid=178

After loading them in there is a problem, nothing works still! Reboot and try, it won’t help.

The reason for this is that kext (kernel extension) signing in OS X yosemite has changed, it seems you need a special sort of developer license to sign kext’s that these drivers don’t have. To fix this you need to put your kext’s into dev mode (you really should be sure you know what you’re doing now):

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

Now if you reboot you the kext will load up just fine, your Arduino should show up and you can get to business.

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