Hi, my issue was that SO_BINDTODEVICE symbol was not defined in /Lib/plat-linux2/IN.py which is generated by h2py.py. This is because the regex is missing out include dirs with "-" in the name. In my yocto cross build system this define is in asm-generic, don't know about other build systems. .../usr/include/asm-generic/socket.h:#define SO_BINDTODEVICE 25 so could you please change following regex in h2py.py (patch attached) -p_include = re.compile('^[\t ]*#[\t ]*include[\t ]+<([a-zA-Z0-9_/\.]+)') +p_include = re.compile('^[\t ]*#[\t ]*include[\t ]+<([a-zA-Z0-9_/\.-]+)')