Hi Felix,
thanks for the fast answer. The CR is from January 2019, I don't know the revision. So I hope it should be fine with 1.0.0 and it actually works quite well with that version. But as I said, it would not use the OLED after powering off after firmware update and then powering it on again. The delay fixed that for me.
My CR does not work so well with the newer one. Your description about unstable ADC sampling seems to match what I am seeing. I quite like the FW 1.1, it has lots more features including the USB debugging. Especially I am missing the USB logging. But I guess it is easy enough for me to add it. So that's what I will do.
Thanks,
Stefan