sorry for the late response.
After comparing both I2CSensor implementations (down to some IO-related UnixDevice class) I could not resolve my Dexter dIMU I²C communication issue.
To proceed with my main objective I’m using the HiTechnic tilt sensor now which is already implemented in MonoBrick Firmware. It is an I2CSensor too but/and it works fine. I’m doing some research concerning timing, threading and so on in order to get a responsive/reproducable balancing loop solution. Further more I’m working on various details, e.g. wondering if (and hoping that) there will never be a time-consuming garbage collector or background system task that breaks my balancer activity.
I think I’ll come back to the dIMU later, keeping you up-to-date of course.
Best regards, Martin