So channel B definatly works.
Out of the box how the drivers are setup it's configured as a UART. However there's some soldering pain to be had hooking up wires to the 0.5mm pitch. But it does work fine.
I haven't looked into how you change it to SPI mode, I'm guessing it would need a different config file?
Why the hell they didn't just break these pins out to a header is beyond me. Total fail...