@retro junkie - I have a few thoughts. How are the contacts on the system? Could it be a corrosion issue or something else with the physical cart? Maybe it's a physical damage of some sort.
Outside that, I'm not sure it would be an update issue. I guess it could be, but the only way to know is to try to update your 3DS and to see if it works.
What are you thinking of for 1st steps? If it's a cheap game, you might be able to buy a 2nd one in and see if there is an issue with that one as well. That would or should fail if it was an update scenario (though not 100% fallible).
BTW - My original DS did play online... I played Tetris online with it... and it was a lot of fun.
Outside that, I'm not sure it would be an update issue. I guess it could be, but the only way to know is to try to update your 3DS and to see if it works.
What are you thinking of for 1st steps? If it's a cheap game, you might be able to buy a 2nd one in and see if there is an issue with that one as well. That would or should fail if it was an update scenario (though not 100% fallible).
BTW - My original DS did play online... I played Tetris online with it... and it was a lot of fun.