If you clone a device you may well infringe someone's patent. A patent is usually drafted with claims in broad terms. Using the PK2 example, let's suppose the PK2 is protected by a valid patent with a claim which reads "A device for programming a microcontroller, having a first port for connection to the microcontroller via a socket, a second port for connection to a PC, and a data processing unit coupled to both ports.". Any clone falling within the scope of that claim will infringe the patent, even though the hardware and/or software is different from that actually used in the original PK2.
Be aware that patent lawsuits can be VERY expensive!
Alec