Save at the Volcano Entry statue, then activate BiT (using the Red Chu is the easiest way). Perform a BiTWarp using the Bazaar Statue; the positioning is important here. The Bazaar Statue should be centered in front of Link, and you should be about two steps away. Done correctly, you'll use a Goddess Cube to clip through the floor OoB, and fall into the Mogma Turf loading zone.
This skips the area leading up to the Digging Mitts cave in Eldin. This trick is not used in 100% because you must drain the lava anyway to get a Goddess Cube.
The best strategy for the Digging Mitts fight involves gathering all of the Bokoblins in a small area and destroying them with a single Skyward Strike. Start by running through the room diagonally towards the back right corner. Climb onto the wooden platform and move back along, charging a Skyward Strike. Once you get the attention of the Bokoblin leader in the corner, drop down and run towards the wall, then turn and shoot a horizontal Skyward Strike. If the Bokoblins have gathered correctly, they will all fall to that Skyward Strike.
If some Bokoblins are left alive, you can continue to jog back towards the Mogma, charging a second Skyward Strike to finish off the stragglers.
Using Reverse BiTMagic, it is possible to avoid collecting the key shards to enter Earth Temple, and instead trigger the cutscene to enter Earth Temple early.
The corresponding Skyloft flag is pushing the gravestone at night to open the shed leading to Batreaux's house. This can be done as long as an early game file exists that allows access to nighttime BiT without crashing. Unlike most RBM tricks, this flag does not have to be committed with an environment change; rather, the cutscene will play as soon as Link enters the trigger area, which includes the Temple Entrance statue.
The trial gate to access Din's Silent Realm can be loaded into Eldin using Reverse BiTMagic. This doesn't save time on Eldin, but does allow you to skip completing the Sandship, as Din's Flame automatically grants you Nayru's Flame if you do not already have it.
The corresponding flag on Skyloft is the five crystal reward conversation with Batreaux. The final textbox of his conversation (which is the second after the Medium Wallet textboxes) can be cleared at the same time as starting your file. In order to access Batreaux in BiT, we use BiTMagic to unlock both the shed door leading to him and the door to Batreaux himself; this is most easily done by a file saved in Eldin after beating Earth Temple, which has talked to the Mogma right outside the Digging Mitts cave.
While this RBM can be done on the first visit to Eldin, the gate will not appear until after the Amber Tablet has been placed, due to Eldin being on the wrong layer until that point.
In an any% speedrun, the second flame wall leading to Fire Sanctuary is a problem, since normally Clawshots are required to feed water to that frog. Thankfully, this flame wall can be doused using Reverse BiTMagic instead.
The corresponding flag is the Shiekah Stone cutscene near the Sparring Hall. In order to achieve this during BiT, you must have obtained the Practice Sword already, and you must save a file at the Lower or Upper Academy statues during BiT.
Using Reverse BiTMagic and Faron BiT, it is possible to enter Fire Sanctuary without obtaining the Water Basin from the Water Dragon to douse the final fire wall. This also skips the entire Scrapper Escort sequence.
There are two ways to perform this RBM.
This method uses the outdoor gratitude crystal on the Lumpy Pumpkin to perform the RBM. This version is thought to be faster by about 15 seconds. First, land in Faron during Back in Time, then return to the sky while enabling the dive button. Then skydive to the Lumpy Pumpkin from within the loftwing tutorial, then sleep to night. Exit the Lumpy Pumpkin at night and perform the RBM with the crystal.
This method uses the Fi Text at the start of Farore's Silent Realm, which can be accessed using a file that has the gate ready. Land in Faron during Back in Time, then enter Faron Woods with the file that has the gate ready. Enter the trial with the Run File selected, then start that file at the same time as clearing Fi's final textbox, which is the third one after the text option.
Doing the Scrapper Escort quickly is the optimal strategy, being about 7 seconds faster than the Scrapper Escort Skip. It is also the only way to access Fire Sanctuary if you are skipping Clawshots, but not doing the Water Basin Skip.
Upon arriving at the Volcano Entry with Scrapper, return to the sky by the nearby bird statue. Land back down at Temple Entrance, then deathwarp with bombs. This will warp Scrapper to you, allowing you to skip the first half of the escort.
To reach the Volcano Summit from Earth Temple, use your bow to kill the front left Blue Bokoblin, then move to the left of his hut; the others should leave Scrapper alone. Hit the Iron Shield Moblin with four charged bow shots, then run up his shield and jump over him. Seven slashes and two spin attacks will defeat him.
Make sure Scrapper is following you here, then hug the right wall of the tunnel while jogging (not sprinting) forward. Once the Bokoblin Archers see you and cry out, start sprinting and pass on the left side of the Iron Shield Moblin. From there, good movement to the Volcano Summit should let you reach the loading zone before the enemies destroy Scrapper.
Once in the summit, hug the right wall, then briefly duck into the archway on the right before continuing. This activates a small group of Fire Keese between the entrance and the two Lizalfos ahead; the movement is designed to have Scrapper avoid the first larger group of Fire Keese at the entrance and get stuck on the smaller group. You can then sprint as quickly as possible to the loading zone leading to the Fire Sanctuary, and should reach it before Scrapper is destroyed. This is the most inconsistent part of the escort.
While this method is about 7 seconds slower than the optimal escort strats, it is much more consistent.
Once you have arrived at the Volcano Entry with Scrapper, go over to the bird statue and return to the sky. Land back down Outside of the Fire Sanctuary and activate BiT. Perform a BiTWarp using the Upper Academy Statue; the positioning is important here. One position that works is next to the statue on the right side; the left side also works.
Link should land on a ledge at the edge of the Sanctuary's roof. Carefully move forward, draw your clawshot and aim for the vines near the Lizalfos, then dodge or kill the Lizalfos and clawshot across to the ledge with the Goddess Cube. You can now run back to the Volcano Summit, where Scrapper will appear. Head back to the Fire Sanctuary entrance to lower the firewall.
The reason the BiTWarp is required is that there is a Fi trigger encircling the bird statue that does not allow you to normally leave that area.
If the first part of Bokoblin Base goes nearly perfectly, it is possible to reach the moving lava platforms between the Clawshot and the Whip area one cycle earlier than usual. The window for this is quite small; one minor mistake or delay in the first segment and you will miss this early cycle. There are several small timesavers in the first segment to aid you:
It is possible to use a sidehop to skip the first Bokoblin guard. After talking to Plats, climb the ledge and run to the fence corner at the very edge of the lava. Turn to face the fence and sidehop. If you have the right angle, you'll land next to the fiery ash on the lower level and can run to the next digging spot.
In the first underground segment, it is possible to hit the first bomb downward, then crawl past it, turn around, and hit it back upwards. This saves having to wait for that bomb to respawn again.
The key here is to stop when Link's left hand (our right) is forward, essentially one crawl away from the bomb, then hit it from there.
When Bokoblin Guards are stationary, it is possible to sprint past them without being caught. This is particularly useful on the two Bokoblin guards after the Gust Bellows; they can be run past, avoiding having to wait or use the Gust Bellows.
There are two small timesavers in the area around the Whip in Bokoblin Base.
It is possible to skip the cutscene that pans around the Whip area when you first enter it. By climbing the ledge with the fence on top of it and using the correct angle, you can sidehop over the trigger for the cutscene.
After obtaining the Whip, you can skip using the peahat to get over the gate near the Volcano Ascent statue by jumping off the right-hand side of the bridge at the right angle. Done correctly, Link will land on a small ledge, then jump again and grab the ledge on the other side of the gate.
In Bokoblin Base, there is a small camera-panning cutscene when you first reach the Earth Temple area. It is possible to trigger this cutscene and still make the first platform cycle going to the Slingshot. You need to use the Clawshots on the peahats to catch up to the floating platform and drop onto it before it floats too far.
If you are too late, you'll either fall into the lava, which with 2 hearts will cause you to respawn all the way at the bottom, or have to wait for another platform cycle, losing about 20 seconds.
Using precise Brake Sliding it is possible to push a bomb flower all the way over to the rocks blocking the air vent to the upper level of the volcano, thus gaining you access to the fourth and fifth key shards early.
While this saves about 40 seconds, it is clearly a TAS-only trick.
It is possible to use an Extending Blow to skip to the fourth and fifth key shards from the first Bokoblin huts. After collecting those, you can resume your normal climb to collect the first three key shards.
While possible in real-time, this trick is quite inconsistent, and only saves about 2 seconds over the normal route. Thus, it is generally considered to be either unusable or a segmented-only trick. A TAS would use the above method instead.
It is possible to skip re-obtaining the slingshot during Bokoblin Base. In order to get the Bombs without the slingshot, first use the Gust Bellows to pass the first two Bokoblins and reach the searchlight. Climb onto the ledge with the fence and sidehop to get to the other side of the light. Then sprint into the light and immediately dig into the ground. If done correctly you'll end up underground and can continue to the bombs.
This trick is extremely difficult, as there is no known setup for the very precise sidehop, and the timing to get into the burrow spot is also very precise. At the moment it is generally considered to be a segmented or TAS only trick.
At the end of the Bokoblin Base segment, it is possible to skip the cutscenes showing the drawbridge lowering through a series of short jumps.
These jumps are extremely precise and save only a short amount of time; thus this would be considered a TAS-only trick.
It is possible to use the bomb flowers near the first Pyrup to drain the lava surrounding the Mogma Turf early. First throw a bomb flower up on the ledge near the two skulls, then pick it up and throw the bomb over the wall to destroy the plug. You can then immediately enter the Mogma Turf.
The angle and positioning on the second throw is precise; you need to be about three steps away from the wall on the right, and the angle should be as close to the wall as possible.
This trick can be used in 100%, but is only just faster than going around the long way. In any% and All Dungeons it is obsoleted by the above BiTWarp.
Once you obtain the Gust Bellows in Bokoblin Base, you can use it to distract Bokoblin guards. Z-target the Bokoblin and blow the Gust Bellows in its face, then circle around it and back away. When you're far enough from the Bokoblin you can continue on normally.
This is not used in runs because any guard you need to avoid, you can just sprint past, which is both faster and safer than this method.
After retrieving your adventure pouch in Bokoblin Base, head over to the right and climb up the walls until you get to the boulders blocking the sand slope. Sprint towards the wall on the left to climb it and jump back down near the bird statue.
This is not used in runs because a deathwarp after the adventure pouch is faster.