[Other✓] How do I change items found on the ground? (HeartGold)

[Misha Da Gama]

(Repost because I'm stoopid and didn't know how prefixes worked)
I'm working on an enhancement hack of HeartGold, and I'd like to change some of the items that can be found on the ground in poké balls. Not trying to add new balls, just changes to what are in existing ones.

I haven't been able to find any information about how to accomplish this. I'm not afraid of editing hexadecimal values, but if I have to do that, I'm not sure which narc to look in. Thanks!

 

[Buffel Saft]

I've only ever done this in Platinum and haven't kept up with the DS hacking scene, so it may not be the best way to do it anymore, but you'll need to hex edit the script narc (in Plat that's scr_seq.narc, not sure what the HGSS equivalent is). The item balls are just scripts, but they don't appear in PPRE or SDMSE, so you'll need to search the file for 28 00 08 80 XX YY where XX YY is the item ID in little endian (you can get the ID from here).

E.g. if you want to find a Potion item ball, which is ID 0x0011, you'd search for 28 00 08 80 00 11.

If there are multiple balls with the same item you'll get a few results, but you can figure out which one is the one you want to edit. The item balls on each route are usually close together, so if there's something distinctive like a TM nearby you can assume you've found the right ball if you see that TM's item ID close by. To edit the item and check you've found the right ball, replace the item ID with the new item ID, build the ROM and check if the item was changed. Don't forget to reverse the ID bytes!

E.g. if you wanted to replace that Potion with a Life Orb, you'd change 28 00 08 80 00 11 to 28 00 08 80 0E 01.

Hope that's helpful!

 

[Misha Da Gama]

That's so helpful! Thank you so much! Yeah, I know what the scripts narc is for HeartGold.

For anyone else reading this, this is a link to the HGSS file system, and it's been very helpful.
https://projectpokemon.org/home/docs/gen-4/hgss-file-system-r21/

 

[Misha Da Gama]

Update for anyone else curious about this: In HGSS, the right narc is definitely a/0/1/2.
Also, instead of 28, it's 29 in HGSS.
Also also, the values for the items are written backwards. So a potion would be 11 00.

So… 29 00 08 80 XX YY
And interestingly, these are followed by
29 00 09 80 XX YY 16, and that seems to affect the number of items you get from the ball.

So glad it's working!