Hi Ed,
I'm sure the first longer cable was a "real" one, but thin & a low quality type - I've seen here in a discussion others having the same issue, but as I've had a similar "ghost effect" some time ago, I instantly grabbed a short cable and then the update worked smoothly ( as soon I've noticed, that I first had to delete the old image before downloading the new one HI )
You can check if D+ and D- are routed through the cable, but in my case, the issue was, that the PC detects the device, wants to access the descripting object, and fails instancing the correct driver. A short cable solved that at a glance!
( BTW this issue often happens with external HDD's via USB, when cables or connectors are long used and weared out!)
Thank's for picking up this issue!
73 de Elmar | DH0GME