There is a new way to clip out of bounds in the Castle Collapse room that we wrong warp to after Fire Temple. Due to this, we can get to a lower part of the castle interior without having to go to the castle exterior, where a cutscene would play showing the death of ganondorf. We now get to skip that cutscene, skip void warp, and go straight to Ganon.
There is more, though. Normally when you finish the collapse segment (at the "kiss") a cutscene plays of the castle falling down before the Ganon battle begins. This cutscene shares a flag with the cutscene of getting thrown into the Gerudo jail. When the flag is 0, the cutscene will play, and when it is 1, it will not play. It is normally set to 0 when you watch ganondorf die, zeroing out any potential for it already having been 1 from getting caught in Gerudo Fortress. However, now that we skip the ganondorf death cutscene with this new clip, this flag is still set to 1 when we finish the collapse segment, and we get to skip the cutscene of the castle crumbling. These two cutscene skips save like two minutes alone
There is still more lol. In previous routes, we needed to have Farore's Wind on the B button during the collapse segment so that void warp worked out properly. Now that we skip collapse, we do not need Farore's Wind on B. This opens us up for other options on the B button. The best one is Eyedrops, which allows us to skip even more of the Biggoron Sword trading quest. (We will never see Odd Mushroom, Odd Potion, Prescription, or Eyeball Frog in this route).
All told, this route saves about 4 minutes from the recently-constructed "equip duplication" route, which saved a minute over the one before that. In the last three weeks, hundo has gotten 5 minutes faster.
TL;DR Shit's fast af. Sub 4 is very possible.
Route doc by dannyb: https://docs.google.com/spreadsheets/d/1kHNO2x1b0EvhcIsjVgr-2olrS_YA3DO20ipXrD9AIYk/edit?usp=sharing
Timing video by fig: https://www.youtube.com/watch?v=5LEGQDe-kFs