Hi!
I had the problem which many users have. Now i think i have the fix.
Go to "Device Manger"- "Ports"- search for "SPRD"- right click and "Update Driver"- "Browse my computer for Drivers"- "Let me pick from a list of available drivers on my computer"- try all the Drivers in the list.
U dont have to restart the PC (in my case).
Now it should work.
Please let me now if it works!