I can't modify register SPIxC1 in PKW01Z128 CTNV1315A, in 1st revision (PKW01Z128 CTWA1242A) SPI worked.
Could you provide more detail about the issue?
I suppose you are using the same code, which worked with Pre-production silicon but that is not working with production silicon. So if my understanding is correct you need to change the pins related to the SPI port.
According to Reference Manual, see the SPI interconnections between Transceiver and MCU.
Hope this helps,
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