Calum Knott

I'm currently employed by Didactic Services, a FESTO Partner, as a Senior Applications Engineer.
I'm currently the WorldSkillsUK Mechatronics Training Manager
I'm also a Visiting Lecturer at Middlesex University
Occasionally I can be persuaded to Freelance!

Contact Me

These posts are archived
They were written with an old blogging platform, and are no longer really maintainable, however as they are linked too from various pages on the web - it seemed a good idea to try and archive them. I have written just enough code to get them to display - but there will probably be a few broken links and images.
Any major queries - feel free to contact me


15 / 7 / 2015


Just a mini blog post to say that if you find after updating to EL CAPITAN, that any of your CH340G based arduinos are not working, here is what you need to do:


This is potentially unsafe

In El Capitan OSX 10.11, this kind of modification is blocked by a new feature called "System Integrity Protection".

It is also known as "Rootless".

The feature prevents both modifications to your system files, and to system processes whilst they are running (even if you enter your password for administrator access).

You can turn System Integrity Protection off. "rootless=0"

But… it affects all the new protections.

You have been warned,

Here be dragons

Step 1

First install the drivers, like normal, from

Step 2

Then open terminal and type:

    sudo nvram boot-args="kext-dev-mode=1 rootless=0"

This is different from the Yosemite command:

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

UPDATE as of Beta 2/3 an additional step is required

Step 3

Restart, hold CMD-R during boot, and jump into recovery mode. Then turn of SIP

Images 'Borrowed' from BinaryAge


Images 'Borrowed' from BinaryAge

Step 4 Optional (If still not working)

Remove usb.kext from /System/Library/Extensions and then repeat the above steps