Does this method still work with Splatoon 2?
Depends what version of the Game you are trying to update to.
If the Game update requires a system version higher it may update. Keep an eye if you go to transfer you'll be able to tell if system update is included.
--------------------- MERGED ---------------------------
Didn't read the whole thread *SHAMEONME*
But, will this method also work for Game Content?
I recently bought LA Noire on Cartridge, and didn't know that this Game needs additional files...
As long as the Game update you are transferring doesn't require/apply a system update it should be ok. I do not know for sure.
I can confirm that NBA 2k18 was the same where you could only play one on one. No main menus or online without additional game data. I was able to transfer game data from another switch, game data for NBA 2k18 which did not require a system update for the game update.
You'll notice if the system update is being transferred with the Game data. You'll see something about system update, don't quote me. If it's just game update then you may be in luck.
This method may just be your solution, was for NBA 2k18 cartridge game data was required. All good now. Good luck.
Some say this method is risky but my how many people it has helped and get out of a jam.
As always people just be cautious of game updates that require or also include system updates. Only a select few to worry about for now, kirby latest update, Xeonoblade Chronicles 2 latest update, few others.