Update, so I got the glitch to work in both Red and Yellow. Took me a few days and about 10+ hours of ingame time from scratch (the glitch itself takes about only 1 or 2 hours to setup). I got my first perfect Mew (Red) and Pikachu (Yellow) - max DVs and max stat experience. However, upon trying it again on my Yellow, I forgot to do a very important step of the glitch and bam, it crashed my game. After restarting my save got deleted! I'm so salty. But it's all my fault. The glitch is totally legit as long as you follow the instructions exactly. It is a very dangerous glitch indeed, nothing could be worse than corrupting your save file! However, if you pull if off, the pay off is definitely worth it.
Ok, so I don't know if it's necessary to make a separate thread for this, but here is how you do the glitch:
1.) Get the 8F Key Item (WS M for Yellow)
2.) Setup the Item Inventory
3.) Setup your Bootstrapping Box party
4.) Execute the arbitrary code
I can't go through all the details, because it's so long that I have to create a separate thread. I think I will if this gets more attention. So you can watch
this instead. If you have Yellow, then check
this. The video is very comprehensive and will guide you throughout the entire process. It's a very good tutorial. Make sure you have time when you do this glitch. It is an advanced glitch and ridiculously tedious! It sucks I have to restart Yellow again after all that, but I have a complete team of flawless with my Red so I don't mind.