Mother had the same issue, it's a bug.
hard power off, connect original charging cable (usb is slightly deeper than usual). Make sure the charger has a decent current output.
fire up, update.
Not a member of The Register?
Create a new account
Remember me on this computer?
The Register - Independent news and views for the tech community. Part of Situation Publishing
Join our daily or weekly newsletters, subscribe to a specific section or set News alerts
Biting the hand that feeds IT © 1998–2019