This command allow to stop kernel "urgently". This commande is no-safe, because threads & process aren't correctly closed. This command close file descriptor in order to no corrupt this.
The return on FreeDOS car be hard.. in fact, Cpcdos manage his segmentation, memory, so according machines, it's probable that a partial FreeDOS memory is corrupted "Invalid opcodes".
I advise you to use command :
This command take more time, close all process, thread and file descriptor, launch garbage collector for bitmap memory and close kernel properly.
Stopping Cpcdos and try to return to FreeDOS