what cable to use for firmware update

You need USB at the laptop end, and USB miniB or rs232 at the Qute end, depending on the socket it has. I thought the new Qute had miniB, though the manual online shows the old rs socket. The PDF instructions for the download will tell you if you can go straight to the new firmware. I think you can, but do check.

I think you're looking at the wrong guide.  As HH says, it's just a mini USB on the Qute2 end, and whatever usb your computer wants at its end.

Thanks for the replies.

Would something like a Kindle lead do the trick?

Sorry, just realised it's more like a digital camera lead!

Thanks again!

It could light your fire .

If the plugs fit into the sockets you should be fine.  More important is to read the instructions for the upgrade before you do it, and even more important than that is to follow the instructions. 

So do make sure you have done the driver updates, do make sure you have the PC / Mac and Qute all with wired connections to the same switch / router, etc.

I have done multiple updates on Qutes, a Uniti and a SuperUniti and provided you read and follow the instructions you should be fine.

Just made an attempt to update the firmware and have downloaded the USB driver from the Silabs link as per the technical notification.

When extracting the driver it will only allow me to install the x64 version to my laptop.

Now, when I get to the 'Connection Check' section of the technical notification and click the drop down arrow in order to 'Select serial port to use' all I get is a blank box and the 'Next' button is greyed out.

All connections are as they should be.

I have no idea what to do in order to resolve it, but can only assume it is a driver problem?

Any advice?

Thanks