I'm on the paparazzi/spi_driver branch, recompiling paparazzi from there. When I do "make clean; make", I'm getting reference errors checking out libopencm3:
fatal: reference is not a tree: 4e4496f70d00fe24b2c5d594d6500f537eeb6478
Unable to checkout '4e4496f70d00fe24b2c5d594d6500f537eeb6478' in submodule path 'sw/ext/libopencm3'