It appears that the values defined for RPL_NODE_IS_ROOT and RPL_MAX_ROUTING_ENTRIES in the Makefile via CFLAGS are not recognized in sc_rpl.c (my guess: they are only visible to the rpl module?) Therefore RPL_MAX_ROUTING_ENTRIES is always set to 0, no matter how the binary is compiled, thus resulting in the output "No routing table available" for root nodes.