Updating ps2 firmware
0- If you installed a PS4 Update Blocker you'll need to Remove PS4 Update Blocker before you can update your Play Station 4 Firmware version.1- First of all, you gotta download the 4.0.1 FW in a PUP file, which you can get clicking this link (mirror here).
9- Connect the FLASH drive to the PS4, followed act connect via USB the DS4 (Dualshock 4 Controller) and press the PS Button.
Update using the Internet Use your PS4™ system's network update feature to update the system.
Update using a disc Use an update file contained on a game disc to update the system.
Use this update to install system software version 5.55.
Always update your PS4™ system to the latest version of the system software.