Just received my Tetra.
Powered by the provided PSU, Boots, connect to http://172.16.42.1:1471
Select update file, confirms file is good, says it's starting the update which will take 5-10 minutes.
Sometimes it comes back to the update file selection page almost immediately, sometimes it take 10+ minutes.
But it always comes back to the update file selection page.
Tried with Firefox, Edge and IE.
The blue led is permanently lit.
As an aside: why is there no troubleshooting guide? I'm sure I can't be the first person this has happened to.