MUC terminal 2 had the arrangement that you could make any connection without needing to go through security again, but they constructed another level for insecure flights from outside Schengen. If you arrive from the US at MUC however you don't need to go through security again for any connection as you will then exit the jetway at level H and not level I which is the normal level for arriving non Schengen flights.

I think this may be true for FRA also, but I am not 100% sure.