Why is my update taking so long?

[AC Question]

I knew my phone was going to update overnight as that is the choice I selected. It turned itself off at 5:18 AM and it will not turn back on at 9:10 AM. Is this too long? It said I would be unable to use it during this time, however does it turn itself back on when the upgrade is done?

 

[belodion]

It will reboot after the installation is completed, but if you are not in attendance, it will then sleep.

 

[B. Diddy]

Welcome to Android Central! Which phone do you have? Press and hold Power for 10-15 seconds--does it power on?