Hi,
I tried with STM32F103C8T6 SPI port 2, but it didn't work, maybe someone can compare the code with the SdFat library, because SdFat already provides for use with SPI2 port:
// Use second SPI port
SPIClass SPI_2(2);
SdFat sd2(&SPI_2);
Source: https://github.com/greiman/SdFat/blob/master/examples/STM32Test/STM32Test.ino