Webcam Drivers extra to provided by DietPI

Hi everybody
So far my experience with DietPi has been fabulous, running on Intel(R) Core™ i5-4590T micro PC.

However I can not get the webcam to work on USB for my octoprint set-up. The camera is Jieli Technology USB PHY 2.0 device, and from last time it was installed (on an OMV6 system that was replaced with DietPi) I seem to remember I had to add additional drivers, but can not remember exactly which.
Mjpeg-streamer just shows a blank page, Motion Eye correclty identifies the device as /dev/v4l/by-id/usb-Jieli_Technology_USB_PHY_2.0-video-index0 but can not open it.
Any thoughts how to fix please, I can not seem to find Debian drivers.
Thanks and Regards

Sorry, found it was a faulty usb extension cable and nothing to do with the excellent Dietpi software