OK - plugged in my other 5222L h/w, and was surprised it was working. I thought it had failed again and had it unplugged for a while.
I upgraded the F/W via the app, and that went smooth, took 5 minutes or so. Firmware Version: 1.14.
IE 11 works with win 10 1607 and the NCS plugin.
Trying to install updates on other win10 test machine, stuck at 99% downloading updates. Will try to confirm this 5222L works there, and then upgrade to Win10 CU.