The Pi Entertainment System (PES) is a graphical front end for a variety of games console emulators that has been written in Python which is intended for use on the Raspberry Pi. This repository contains the PES source code and operating system customisation scripts.
At some point it would appear that the calculation of the "rasum" for MegaDrive and SNES games changed (and possibly others).
Need to check if the algorithm for rasum has changed.