I don't quite remember, honestly; I think that I was trying to use the old method of a button as a filename prefix, then holding down the button during boot, when I actually had to hold the start button during boot and select the payload
Uh-oh... I'm stuck on a black screen & can't even hold down the power button to power off... This may be a problem. Any advice?
Never mind, I just didn't know how to use New Luma
I used steelhax. I just downloaded the zip here and followed Plailect's guide after running it and downgrading. I don't remember my initial primary entrypoint (it was a while ago), but you can use SoundHax.