I have an old 3ds XL on Luma3ds 7.0 with gateway payload. I just followed this tutorial before https://gbatemp.net/threads/tutorial-using-luma3ds-with-gateway-on-v2-a9lh.431691/.
All files will go to 3ds memory card and not on gateway. When I boot to gateway, I press down dpad + power on. Then...