This is a useful thread to link people to when they say they are using 3rd party cords.
I have found some problems are due to people using 3rd party cords or adapters.
I have even experienced this myself:
I recently had a V3 Pro that failed updating the firmware after more than a dozen attempts. It was on a 3rd party adapter and a long 25ft 3rd party cord. I finally moved it back to the cord it came with and tried the update again and this time it magically updated fine. Then I moved it back to the long 3rd party cord. 
Yes, I know I may continue to have some problems with it. I just barely bought a voltage/Amp tester that will do USB cords, and I plan to eventually fix the issue like Newshound has admirable organized here.
Point is, I can personally vouch for the fact that it does in fact matter and this is a really good resource we can refer people to in order to help them with similar struggles. 