This mod removes the mirroring effects from Master Quest in OoT3D. It's based on this project by n3rdswithgame: https://github.com/n3rdswithgame/z3d_hacking/blob/master/mqum/mq/build_patch.py
I made files for both the USA and EUR region, and they work on 3DS and Citra. You can use either the IPS patch or the cheat code, but if you choose the latter you should enable it on the title screen and when you need to disable it you'll have to close the game entirely.
To build the files, just run build_patch.py. By default it builds for USA. For the EUR files, run the script with the --eur flag on the command line.