Calculating HDD0 and HDD1 Offsets and Sizes on a nand hdd backup 

backup.img (obtained by using a tool called HDD Raw Copy Tool, link hddguru.com/software/HDD-Raw-... )
eid_root_key (obtained via cfw such as rebug or evilnat)
ssl's /sorvigolova's ps3encdec tool (link github.com/Sorvigolova/ps3enc...)
hxd or any other hex editor (link mh-nexus.de/en/downloads.php?...)
calculator (windows calculator is sufficient for this)
WSL to make this easier
dd tool to copy specific regions of the backup file