Subject says it all. Used the .update file method with the tar file. The upgrade worked perfectly. All addons intact, settings intact etc.
But when I tried to go in with Winscp afterwards (same method I logged into the Kodi box to put the .tar file in the .update folder), the password I had been using doesn't work. Checked numlock and capslock etc., cut and paste password from file, typed many times. Can't log in on the network.
Any suggestions? I'm on a Windows network, the Kodi box is an Intel 64 bit I5.