how can I update a 2008 g35 gps?

 

The GPS antenna replacement is covered in the FSM and requires removal of the console components, it's hidden behind the clock. GPS is pretty much standalone tech that doesn't require any sort of updating.

Are you asking about the NAVIGATION system, I think it requires Consult II (dealership) to install the map pack and there is a fee for vehicles not covered by warranty.

In all honesty the factory nav is pretty weak compared to aftermarket options, you would be better off spending the cost of the map pack towards a newer Garmin with lifetime map updates, it's interface is MUCH faster and literally better in every way, use the factory nav as a place to adhere the suction cup for the Garmin

http://infiniti.navigation.com/home/...InfinitiNA/USD
https://buy.garmin.com/en-US/US/cOnT...motive-p1.html