BW: How do overworld items work?

[WheatleyTheMoron]

I'd like to change overworld items in BW, like the thunder stone in Chargestone cave, and I understand it's an NPC that calls a script from outside the map's script file, but I'm not sure how it calls the script exactly, where the script it calls is or how to change it. A similar thing happens with trainers too if I were to guess. I just haven't seen much about that online. 

If anyone has anything to share regarding this, that'd be great.

Edited May 7, 2021 by WheatleyTheMoron

[Monty3540]

I did manage to work this out at the end of last year

Once I have some more free time after next week, I can try and dig out my notes for this

As I was able to alter a few items, such as making the Red Orb and Blue Orb appear in N's Castle in B2W2, and use that to trigger other legendary events in my ROM hack

If I remember, alot of the information for calling the items that are in the overworld, is found in a late Script file (around 1240-1241 in B2W2), not sure what it would be in BW - but I imagine it is similar, with the Script file being a late one.

I would try scrolling through NPRE 1226 to see if you can find it. Use the item list from Bulbapedia as your reference for the Hex number of the items.
If you search for an item that only appears once or twice in the game - such as the Relic Crown or Comet Shard, you will start to work out how the script works and what location it refers too.

There is a bit more too it than that, but if I remember - that is the main gist of it

Hope this atleast helps you have a starting point!

[Monty3540]

Hi @WheatleyTheMoron, do you require help with this still?
I have finally had time to get back in BW and B2W2 hacking so I have been playing with Overworld items editting again, recently in BW
Let me know and I can send some info over from a Notepad log I made as I went along learning