Reports on some forums are complaining that the latest Playstation 4 Firmware 7.50 is causing boot problems. This fiasco is likely to be a real blow to Sony as an unbootable machine cannot have new firmware installed easily.
Even when it successfully boots, it restarts infinitely. It should be noted that not all Sony Playstation 4 units experience this issue. Furthermore, there are also reports that after the update, the console turns on but doesn’t transmit a signal to the television.
If your console is already affected, try booting up in Safe Mode. To start the PS4 system in Safe Mode: press and hold the power button, releasing after the second beep.
If you can access the PS4 home screen but the system software update has failed, go to [Notifications] and delete any existing update files by pressing the Options button > [Delete]. Then go to [Settings] > [System Software Update] and follow the on-screen instructions.
If you are connected to PSN but cannot reach the home screen, start the PS4 system in Safe Mode and select Safe Mode option 3, to update the system software. If possible, connect the PS4 system to your router using an Ethernet cable to ensure that the connection isn’t disrupted.
So far Sony has not made any official announcements over this problem.