Updating iphone firmware takes forever
For i Phone 6s and earlier, i Pad, and i Pod users, press and hold both the Sleep/Wake and Home buttons for at least ten seconds, until you see the Apple logo.
"Launched the update with i Tunes on my i Phone 6 an hour ago.
i OS has a lot of great features but in order to enjoy them you need to update.
If your i Phone or i Pad won't finish downloading, gets stuck while installing, or won't turn back on after it's turned off, don't worry.
After a few tries i finally got it to START installing the firmware.
It has the loading bar on the phone screen but it is stuck at 3/4 of the way complete.
Thanks for reaching out in Apple Support Communities.