Fix a TMAX/APEX TM9S775 replace factory files

I have this TM9S775 tablet. In fact I have two. I figured out how to root it and I think I have access to its base files. It seems that its factory files might be corrupted (before I started tinkering). It starts crashing, apps stop working. Factory reset seems to have issues. Can I copy factory files from one to the other and then reinstall? Which files in which folders? Its a 4.1.1

thanks