Surface Dock - no USB with new Surface Go

[agt499]

Hi all.
Long story short:my Surface Pro 3 finally died a battery death, so I picked up a Surface Go (1) to hold me over until the Pro 8 comes out.

When I plug the Surface Dock (1) cable into the Go, it powers it and drives the two attached monitors fine, but doesn't register the USB devices for keyboard/mouse/audio.
The dock still works completely with the SP3 (and my wife's which is still alive), and the USB devices work if plugged into a hub to the Go's USB-C port, so it's not a driver issue.
Have rebooted/updated/full power off etc to no avail.

Any suggestions?
Thanks!

 

[agt499]

As further info in case anyone can assist, I've spent a fewhours following the process for firmware update of the dock as noted here Microsoft Surface Dock Firmware Update - Technical information for IT administrators - Surface. I ran the update on my SP3 and from the wife's SP3 just in case of differences there.
Per the attached screenshots, it appears that the MCU firmware (Component10 ) - which I would expect to control the USB - now has CurrentFwVersion==OfferFwVersion==78395760, but the DisplayPort firmware (Component20) has updated but not to latest.
Also confirming that Ethernet and Audio which I'd also expect to be related to MCU are no working with the Go either.

Grateful for any clues on offer!

 

[agt499]

Posting an update, in case anyone should stumble upon this with similar symptoms.
After return to the retailer and subsequently distributor, I'm advised that it's being replaced, so probably concluding a hardware failure with the connector.