Last night I successfully modded my Japanese region 3DS with the latest version of Luma. I followed the 3ds.guide instructions, and it was smooth sailing. I dumped a few of my games, and then installed them with FBI.
The first two games, Shovel Knight and Tetris Axis, both booted up in English, and saved properly. The third game, Ultimate NES Remix, showed it’s title in Japanese (even though this is an NTSC region game) and when booted brought me to a black screen with Japanese text. No clue what it says.
I then found a couple games off here to test out, one being Sega 3D Classics, and the other being Mario Maker. Both games were US region, however Mario Maker booted in Japanese. This game also gave me a screen of Japanese, which again, no idea what it said. 3D Classics booted up in English, but gave me a message warning me of the lack of features due to there being no SD card in the 3DS.
Obviously there was an SD card in the system, so I’m unsure what to do. Any help is sincerely welcomed.
I would say it was probably due to your 3ds being a Japanese 3ds at your game being USA. I would try using Luma Locale Switcher or I would try to find a region free cia of the game. 1)Hold select and turn on your 3ds. 2) Check Enable region/language. and ext..code. and press start to save changes 3) Install the Luma Locale Switcher.cia 4) Launch it and navigate to the game. 5) Change the region to USA and language to EN 6) Launch the game to see if it works.