well it is pretty straight forward. it's just that it stores the image in a useless chunk wrapper.
had to do a bms script to convert to dx10 dds files, cause the noesis plugin is whatever. it does not support the normal map compression, that is bc5s using red green, and it's slow af, cause i had to read bytes. i couldn't figure out how to append the chunks. all those different buffer interfaces and it seems they're not all compatible with the conversion and the noetexture function. crap. maybe somebody could find better and faster way.
That's 'swell... So I presume one can do it in reverse then, assuming someone can repack a .PKG file that holds these files?