After studying the documentation of the STM32H747 I'm pretty sure that CubeMX is missing to show at least one alternative pin muxing for the FDCAN. For FDCAN1, according to the document DS12931 Rev , it can be set for instance to PD4/PD5. But the CubeMX PinOutView is not giving that option.
I cannot test this by changing manually the pin setting before next Tuesday. After I checked it I will report back.
Best Regards
Markus
