As there seem to be more interested parties than I originally thought, I would like to present my project for controlling a Buderus Logamatic R2107 / HS 2105 oil heating system.
Have a look at it - I would be happy if there are one or two users who would like to use it in the future.
As always, I am open to feedback, suggestions and enhancements.
@bartek666666 honestly I am not aware about the differences between R2107 and R2105. If I look at some pictures that can be found with google, it looks that it has also the interface for the KM271 board.