Problem with CerBot & CharacterDisplay

I just got a CerBot, connected it to a CharacterDisplay on Socket 1 and … it does not work!
The display itself works fine with a Cerberus.
I updated the Cerbot - firmware to 4.3 and use the Gadgeteer R5 library.
Furthermore I used the Cerbot - integration into the IDE mentioned in

https://www.ghielectronics.com/community/forum/topic?id=18755

and the CerBot - Lib from:

https://www.ghielectronics.com/community/codeshare/entry/926

Has anybody an idea what I made wrong?

By the way…If it would work…,
I wish the Character Display would be of the type which can be read with Backlight off. (e.g. the green ones)

There is an sdk coming in few days that brings the cerbot back. This maybe an easy option if you want to just wait.