This script didn't work very well, so I create a new one: https://github.com/LITTOMA/Archive_Tools/blob/master/mhx_arc_unpack.pyHere it is.
https://onedrive.live.com/redir?resid=B6305612E3C95FBD!686&authkey=!APr7U9cKfAbWSuQ&ithint=file,7z
unzip then you can find named "MH4G_ARC_UNPACK.py"
Tested with MHX and MH3G(U).







