I have an Hitachi HTS545032B9A300 disk that produces click sounds, but not when it's intensely engaged in read activity, only when it's low activity.

After some research it seems that the problem may be caused by the heads being placed in the park position by firmware setting: using Crystal Disk Mark, for each click the Load/Unload Cycle Count value in fact increases by one unit.

I'm afraid that the parking function can reduce the disk life: is there a way to disable the heads parking ?

I was able to do this on Hitachi with the "Hitachi feature tool" present inside the "Ultimate Boot CD". (or there https://hddguru.com/software/2006.01.20 ... ture-Tool/)
By putting the APM to the max value. (and so it is internally saved)

It looks like the same modification that is suggested in various discussions, which should be done with third-party software such as Crystaldiskinfo, Hdparm, or by modifying a Windows registry key (see links). In the first two examples the change is lost with the restart of the PC and must be reapplied.

In the case of Hitachi feature tool probably the change is saved and not lost at each reboot.

What I suggested will normally works on your drive, and will survive reboot.
You have no other choice than re-disabling it with others solutions if your driver/windows re-enable it.

The .iso file containing the Hitachi Feature Tool won't boot on my pc, so I created a Freedos floppy with Rufus and copied the necessary files to it.

I set the bios from Uefi to Legacy mode and the disk controller from Ahci to Ide, then disabled Secure Boot.

I managed to start the Hitachi Feature Tool, but it only detects the Samsung Ssd and not the Hitachi disk: I think the latter is connected to a controller that may require a specific driver.

Any suggestions ?

Try to plug the Hitachi at the Samsung port.

I wanted to avoid reversing the ports because I have to open the laptop, but now it seems the only solution ...

The change made using Crystaldisk works as expected, although it needs to be repeated on each reboot.

Depending of your laptop, it can be very easy to ultra hard to access those drives.
You can eventually plug the Hitachi in another computer if you have an easy access to it.

I cannot help you for a driver, and the port is likely hard coded inside the tool so you can surely do nothing, like your actual Hitachi port is not standard.