Finally ordered some PCBs. Butchered one of my boxes and replaced pcb v1 with pcb v3.0.2.
Back yard testing showed up promising; BNO055 seems quite stable.
Drove some circles and IMU reading showed 361-365° per circle.
Planning to test it during harvest season at combine to see, if it really works.
I made a few more small cosmetic changes, and uploaded gerber files, partslist and other stuff to here Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.
KaupoiMOD PCB v3.0.3