I might be wrong but based on the explanation that's been given about how the game functions/how the double-damage glitch activates, I have a theory on how to carry it over between phases: If you have two tiles on the board, and manage to leave them there until after the boss changes, wouldn't picking them both up THEN continue the glitch? And even with one, do you think there's a flag in the game that says whether it can spawn another damage tile after the boss's transition? I would say, when the boss is down to his last hit, take the oldest damage tile and leave the most recently spawned tile. the game might spawn a second tile and then you would be able to pick both up? Obviously, I haven't read the code, and I haven't been able to create the glitch myself in normal gameplay, so I cannot test it, this is just hypothesis based on what information is given about the glitch in the guide for it.

Based on what I've seen you could carry the DD glitch over multiple phases but at the same time, as much as I've tried, I could not recreate it myself. So I guess Anthonya would be the one to actually answer this question.

Thank you for that, I really wish I could get the DD glitch myself as that would really help reduce the time but... well, that's not been easy. My reflexes are a little too late and so I go "OH I COULD HAVE DONE THE THING" less than a second after the coin hits the ground. disappointing, but it is my fault