Xperia Z3 had software update and now in a continual loop of rebooting, why?

[AC Question]

After downloading a new update, the phone gets part of the way through rebooting then switches off before restarting and doing the same thing. It's been doing it for about an hour and I've tried powering it off but it makes no difference.

 

[the tall guy]

Hi, does the phone have sufficient charge in it? are you able to boot the phone into recovery?