This is certainly possible (also possible for the modem to leave instructions for the phone to perform a remote wipe, for example). The other way around is als

This is certainly possible (also possible for the modem to leave instructions for the phone to perform a remote wipe, for example). The other way around is also imaginable - where the modem temporarily stores new firmware on the RFS upon reception, before updating itself, to reduce its own (likely expensive NOR-based) flash memory requirements.