PS4 Slim cannot associate controllers + System Software problem

I have a PlayStation 4 Slim (CUH-2016A) that suddenly couldn't use controllers: they are not recognized even with USB cable and I can't enter in the PS4 home menu, but they work in the Safe Mode menu (so I exclude USB problems).

Also, I couldn't reach Safe Mode in the standard way (by pressing power button for 7s when PS4 is turned off) but only by pressing power button for 7 seconds, release for 1s, and keep the button pressed again until the second "beep": when I tried the standard way, the 2nd "beep" don't occur after 7s but it takes longer, and after that PS4 just turn off again (without showing anything on screen, it just turn on and off immediately I think).

In the Safe mode I tried ALL OPTIONS and NONE of them worked. Neither Internet or USB update or USB System Software Reinstall, they start but give an error when coming to 100%.

I used another working PS4 (CUH-2016B) to put the previous one's HDD and I was able to Reinstall System Software via USB, and then to enter in the PS4 home menu (so HDD works properly). Then I put this HDD in the faulty PS4 and I got more problems: "Impossible to startup PS4". It asked me to connect a USB with updated System Software for reinstall and when I do it just give me an error. Again, nothing in the Safe Mode works, so now I have 2 problems.

Another detail is that when I plug the AC connector it takes some seconds (approximately 10-15 seconds) for the power button to work, a bit more than the working PS4 used for reinstall the software (approx. 5 seconds).