Ok.well I cant really see anyone with exactly the same problem this just wont complete the update from the tablet the controller looks OK and its done a Battery restart on Solo but then it just sits there.
Did you get the Update complete message on the controller display?
Did it then after pressing the A button tell you "waiting for Solo "
If the answers are a yes, you are good so far.
What did the Solo led colors look like?
- flashing in rainbow colors: still updating, keep on waiting, can take up to 20 min
- flashing red: power cycle and wait for max 5 minutes and it should work then
If any of the answers are a no, contact support. They will guide you through a factory reset.