EU Game on JP 3DS Download Play

[Zizike]

Hi!

I have a Japanese 3DS with luma3DS installed. I want to play Mario Tennis Open with my brother, who owns a European 2DS (no mods installed).
I have the European version of the game installed on my 3DS, but the 2DS' Download Play won't detect the game.

Any way to fix this without changing the region of my whole console?

Thanks!

Edit: tried the Luma Locale changing thingy by setting the region of the game to EU, didn't work