weird_dave:
I have generally found that #3 isn't required if you do #4, usually just closing...#1 is a problem for me as I've had some boards made without the programming port
With regards to hubs (#2), I have been using a powered USB 3 hub...
Thanks for all that. I didn't have any of the 3.0 hubs to tinker with. However, I will keep all this in mind should more wonky things start happening again (Win-d'ohhhs!).
I was suggesting that the USB-device enumeration process for the DUE's native-USB port was perhaps creating a timing issue with BOSSAC. Again - I didn't dive deep into this - just a casual observation. The important part (for me) is that whatever silly, supersticious wand-waving I did, I can now upload!