Hi all!
After nico commit [0] batman-adv stopped working in openwrt backfire ( the crc16 modules is still kmod-crc16 in openwrt stable )
the batman-adv module refuse to load without error message on stdout but saying that crc16 is missing on dmesg
selecting manually kernel modules -> other modules -> kmod-crc16 it work again
[0] https://dev.openwrt.org/changeset/28657/packages/net/batman-adv/Makefile