Big Chest Key

To have a BigChestKey (like in parallel worlds) simply open your ROM in a hex editor, go to offset 0xEC1A (rom without header) and change the 0x66 to 0x64, this tells the game to check if you have the compass if you want to open the big chest. Then replace the compass graphic with a key graphic of your choice.

I didn't know it is that easy. This is vital news, since the compass is somewhat the less important item. The value 66 is probably to check for the big door key, I wonder if the value 65 is to check for the map.

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Question. I've decoded the primary and the secondary locations of dungeon room pointers. So I can build rooms with lots of data in hex, but then Hyrule Magic doesnt read them. The same with the room header properties. So I can build the rooms with maximum possible header used, but only in hex, not HM.

Is there any way to reprogram HM, to read the poiters and save at that spot in the rom within 2 or even 4MB? I don't know how difficult this is to achieve, but I know that HM can actual read the data but can not save it.

The same with header properties. This is fixed on 27502 where the poiters begin. The actual data starts at 27782 and goes to 27FFF, having 87E total space = 2174 bytes in dec. But it would need around double this amount = 4300 in dec. That way all rooms could have maximum and unique header properties.

If HM would read/save this data from repointed area, say 127782 (which is exactly 1MB shifted), it would never run out of room header data.

Yes the value 66 checks for the big door key, in fact you can place any item there to check.

It's been a while that i had the same thoughts about hyrule magic, but unfortunately i have no idea how to do this. I wish we had the program code of hyrule magic, this would make it much easier.....maybe it is only one value to change in hm.exe to make it use the new bank. It really depends on how it is coded. I already searched in the executable with the hexeditor but found nothing......i am sorry.
Is there really nobody that has the source code of this program? That were amazing!

There is another thing i saw. There are 4 places in the code where the game is looking for the big key in your inventory:

1. if you want to open the big chest
2. if you want to open the big door
3. when your inventory is drawed (to decide if the key should be drawn or not)
4. unknown

I really think that 4. is if you open one of this prison-doors (for example where zelda is imprisoned). So one could use this to check for another item, maybe the dungeon map. Replace the dungeon map with a stone fragment for example. The player must find this and then can open this prison door (modified graphic, a stone door with a missing fragment). Three keys in one dungeon, this sounds really good :-D.

Found the value for the Map. At 0xEC1A (rom without header) change the value 66 to 68. Then you need a map to open the big chest. And the map is much easier to gfx-change it into a second key, since it is using the same invetory colours (yellow and white).

Yeah i checked this a few hours before while testing for this prison door and it like i said, the first appearence of AF66F37E (LDA $7EF366 in ASM) is for the big door, the second appearence is for the little prison door, the third is for the big chest and the fourth is for drawing the big key in the menu. At the moment i am working on making the little prison door open when link comes from left or right (front and back works). And then we want to replace the graphic with a little block with keyholes on every side (like in links awakening - gameboy). Then i will try to open this with little keys. Have you an idea whats the value for small keys? I know it is not the same like the items, because when i wanna do this, i need to check for small keys > 0 and then reduce them by one.