1. If it’s not already off, turn off your PS4 (all the way off, not standby).
2. Press and hold the power button for about 10-15 seconds until you hear a double beep.
3. Plug in your DS4 controller to the front USB port (use the same cable that came with the PS4 for controller charging).
4. Press the PS button on your controller, and you should be able to use safe mode. Note: Be careful of what you do in safe mode, you could erase all of the data on your HDD.