It seems you're looking for the (firmware) in RPKG format (a package format used by Nokia firmware update tools, e.g., Nokia Software Updater or Phoenix Service Software ).
If you are looking to restore or modify a physical device rather than emulate it: nokia 5320 rom rpkg
Before diving into the specifics of the Nokia 5320, we must understand the container format. .rpkg (Resource Package) is a proprietary file format used by Nokia’s firmware update tools (like Nokia Software Updater and Phoenix Service Software). It is essentially a compressed archive that contains the core components of the phone’s firmware (ROM), including: It seems you're looking for the (firmware) in