ebtables installer macro does not copy ethertypes file. As result, you cant use readable characters instead of hexadecimal numbers for the protocols. For example, 0x0800 will be represented by IPV4. Add to the install macro the following command to fix: cp $(@D)/ethertypes $(TARGET_DIR)/etc/ethertypes Thanks
Fixed in git, thanks: http://git.buildroot.net/buildroot/commit/?id=d19e39ca25f0e7