https://www.theregister.co.uk/2018/10/26/surface_pro_6_laptop_firmware/

As Microsoft released the first batch of firmware updates for its shiny new Surface Pro 6 and Surface Laptop 2 hardware, owners of Surface Pro 4 fondleslabs afflicted by July's borked update remain in the dark as to when, or even if, their broken firmware will ever be fixed.

Those with a Surface Pro 6 brave enough to run the Windows 10 October 2018 Update are due firmware fixes aimed at resolving pen clicking problems. Battery drain due to a borked Intel Display Audio driver is also fixed. The rest (for the Windows 10 April 2018 Update onwards) consists of fixes dealing with unexpected processor speed capping, interruptions to music services and the ever-nebulous "system stability improvements".