See respective README in Python or Lua or Shell folders
https://gist.github.com/roman-yepishev/c86069d7369e0af98796f199d9f2427a
https://github.com/sh3llc0d3r1337/nb0-extract
https://github.com/GautamGreat/Nokia_NB0_File_Unpacker
https://github.com/asoneofus/v350/blob/d627d61335eaf5bcbc301e84cf11aa2d23592e13/FADG_4.39A/system/core/fih_img_update/nb0parser.cpp