There were more HW boards, could you describe more infromation which HW boards you used? How did you use them? What was the problem?
BNO055 xplained pro board: https://www.bosch-sensortec.com/media/boschsensortec/downloads/application_notes_1/bst-bno055-an011....
Aplication note----BNO055 quick start guide: https://www.bosch-sensortec.com/media/boschsensortec/downloads/application_notes_1/bst-bno055-an007....
Application note----BNO055 UART interface: https://www.bosch-sensortec.com/media/boschsensortec/downloads/application_notes_1/bst-bno055-an007....
You can't directly use USB serial to BNO055 because BNO055 is 3.3V, so you need level shifter.
We already open our shuttle board schematic, UART interface and Driver as below.
If you can design hardware properly, technically you can design your own hardware with BNO055 and test it.
However, there is always some possibility to have hardware issue.
Why not only bosch, but all chip vendors have their own development kit is for customer to verify their software first, then test with their own hardware.