When I click Administration > Software Update
Then click Upload Update File
I select file "pi_2.1device_packs_4-40.ubf"
I get message "No file has been selected."
Don't know why or what to do next.
I dont have a PI 2.1 server to try today, until next few days. It may be a new bug or just you can try to use another browser or try deleting cache/cookies and re-try.