GPS/connectivity issues Galaxy Core 2.

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Have you tried to get a fix outside with the other radios off? Is it able to get a fix with the wifi on?

You also didn't say what service provider you have. I know that when they are upgrading the towers the overall service can be spotty.

 

I'm new here, and it said I had to log out to post here. I am the OP, btw.
I am using Vodafone NL, but I doubt that is the issue because the GPS problem also persists during WiFi.

I forgot to mention, but I do get a GPS fix, but after a while it gets jerky and eventually the accuracy is way off. Could this be related to the unstable connectivity of both WiFi and mobile data?

 

Some devices use the same antenna for all of the radios. It could be the modem (kinda a miss nomer) needs an update. It could be a design flaw.

 

How do I update the modem? This phone is not rooted, I haven't found a safe method yet. Is there a 'simple' and safe way to update the modem?

 

I would find another user that had the same problem first. If I get some time at home and I think of it I'll search what I can to find if your problems are common enough.

 

I already tried Googling.