How to reset ps4 fixes many problems like no video, freezes, controller sync, can not sign in psn, ps4 errors fix, just reset ps4, but if you got PS4 update error message try updating ps4 using usb drive stick.
PS4 USB UPDATE DIRECTIONS
1. format usb drive to "fat32" on PC or Macbook
2. go to http://us.playstation.com/support/systemupdates/ps4/ to download PS4 update
3. install update on usb drive by creating 2 folders.
Using a computer, create a folder named "PS4" then Inside that folder, create another folder named "UPDATE" put "PS4UPDATE.PUP" (ps4 update) file into the "update" folder.