Hello and sorry if I am bumping this topic unnecessarily.
I had all of the same problems when updating with a win 8 self built pc and may have found a fix.
The only difference is that I had to update with usb 3.0 because this was the only port that did not return the cable error.
At first it got stuck halfway trough the update so I had the idea of turning of the built in usb power management of windows and that fixed it.
For anyone wanting to try this i'll explain how:
-Go to control panel -> open power management-> plan settings->change advanced power settings
->find "USB settings"->USB selective suspend setting-> Turn this option to disabled-> reboot and try to update.
This was what got it to work for me so maybe it can help some of you guys having trouble updating.
If needed i'l make a few how-to screenshots to explain the process. ;)
