M109 will only wait for heating without the 'R' Parameter... So how can I prevent the printer from being shut down too early?
M109 [B<temp>] [F<flag>] [R<temp>] [S<temp>] [T<index>]
Parameters
[B<temp>]With
AUTOTEMP, the max auto-temperature.
[F<flag>]Autotemp flag. Omit to disable autotemp.
[R<temp>]Target temperature (wait for cooling or heating).
[S<temp>]Target temperature (wait only when heating). Also
AUTOTEMP: The min auto-temperature.
[T<index>]Hotend index. If omitted, the currently active hotend will be used.