So, I'm guessing you can change your X,y,z location for a save file?
Which would allow you to save with a big bomb, and then change locations.
Or am I guessing wrong?
Sadly, the Big Bomb following you is not something that saves. For that, I'd have more luck replacing one of the NPCs in the Village of Outcasts with the Big Bomb, or changing executable to think that the string for the cult preacher the map data is asking to place is the Big Bomb instead. I can modify the game.
Changing save files isn't something I haven't fully accomplished yet, but I've definitely begun to map out that data. It might actually be easier for me to modify the game's executable to
think that a save file contained different data than it actually does. The 3DS hardware-based encryption/MAC is a pain, and nobody's written tools to fix the MAC yet. (MAC = a type of cryptographically-secure checksum, similar in use to a cryptographic hash.)
Save files actually don't store your X/Y/Z at all - they store which weathervane you saved at. You'll notice that if you save at the side of a weathervane, you'll still end up loading at a canonical location in front of it regardless of where you saved. This means that save file hacking cannot be used for arbitrary teleportation.
However, there are weathervanes in Lorule =^-^= What I'd like to do is play through until I get the Master Sword, but don't go to Hyrule Castle Tower. At that point, save the game at Karariko Village, then hack my save to be as if I'd saved at Village of Outcasts instead. From there, I could see what happens if I do various things. I could answer some current unknowns:
1. Are the portals present in Lorule even if you haven't gone through Hyrule Castle Tower?
2. If they are, what happens if you go through the portals, particularly as it relates to the Hyrule side?
3. What happens if you get near the Lorule Blacksmith's house like this? My current educated guess is that the message you get when you exit that house is actually the master even that triggers the opening of the portals. It'd be interesting to see what happens if you approach like this without having gone through Hyrule Castle Tower, beating Yuga 2, or seeing the creation of Yuganon (the cutscene internally named "Demo 4").
4. If you do see Hilda's message, and her message affects the world, what happens if you then go through Hyrule Castle Tower? As I've been theorizing for a while, it's possible that instead of seeing "Demo 4", you'd fight Yuganon and complete the game.
By the way, the "Documenting" thread on this subforum has a link to a spreadsheet I've been making with what I've determined so far about the save file format. There are a lot of event bits in this game, but the save files aren't very big - 0x1604 bytes each. Mario Paint for the SNES had almost twice as much save data as this game (0x8000 bytes, compared to 0x440C).
Melissa