Just for clarification, updating the GPSv9 (gpsplatinum) firmware is not a requirement. The old GPSv9 firmware only looses a small percentage of packets (not a humanly noticeable flight difference) and it has always been this way; even back to the OP days. It used to simply ignore these bad packets.
It's only now that these bad packets are fixed in the current GPSv9 firmware that the missed packets are reported in the FC firmware; so you know that there is an issue that you can fix by updating the GPS firmware.