In order to rectify the situation, Capcom took the CP System hardware (with QSound) with minimal changes and employed encryption on the program ROMs to prevent software piracy.

As time passes, these batteries lose their charge and the games stop functioning, because the CPU cannot execute any code without the decryption keys.

Consequently, the board would just simply die, even if used legally it would not play after a finite amount of time unless a fee was paid to Capcom to replace it.

In January 2007, the encryption method was fully reverse-engineered by Andreas Naive (Archived 2013-07-02 at the Wayback Machine[7]) and Nicola Salmoria.

In April 2016, Eduardo Cruz, Artemio Urbina and Ian Court announced the successful reverse engineering of Capcom's CP System II security programming, enabling the clean "de-suicide" and restoration of any dead games without hardware modifications.