Homebrew Retroarch Lag (NOOB ALERT)

[Phantop]

Use this tool. You can also download pre-made injects of almost every decent GBA game over on that iso site.

How about preexisting save files? Can I just use a save manager and copy the file?

 

[coinblock]

How about preexisting save files? Can I just use a save manager and copy the file?

Nope! VC GBA saves are unfortunately a little more complicated.

In order to import a save, first you need to rename the game's .sav file to "gbavc" (without the quotes) and place it on your SD root.
Next, you need to run the game you wish to import the save to. Once the GBA game has loaded, press the home button and then exit the title. (You must launch the game first and then reboot or the next steps won't work)
This will reboot your 3ds. As soon as it reboots, start Decrypt9/Hourglass9 via Luma chainloading. (If you followed Plailect's guide, this means holding Start as the 3DS boots up)
In Decrypt9/Hourglass9; navigate to sysNAND options, Miscellaneous, GBA VC Save Inject, and follow the onscreen steps to import your save.
Exit back to the Home Menu and start up your GBA game, and your save should be successfully imported.

Now you get to redo this for any other title you wish to import a save to! Hooray! You can also export a save by doing the same steps, but then choosing "GBA VC Save Dump" instead of inject.

Oh yeah, I think there are some extra steps you need to take for Pokemon game saves, just search the forums here and you should find them.