>>56410223>>56410343Update: I figured it out. It's an NPC I think I missed in the lower left of Pearl Shore (go back down from the sewer entrance, take the lower bridge, jump down and across to the right).
How I figured it out may be relevant to the thread though -- I couldn't find any walkthrough or anyone asking about this specifically, and the few videos I saw ended long before this part, so I got it from the ROM. I found
https://github.com/cosarara. Blue-spider is an alternate map editor that isn't as good as Advance Map for the most part, but has a Python script to dump all maps to files that can then be rebuilt and injected into a ROM. The dump script is broken in the current commit but commit 954d4e9 is good. Red-alien is a script editor that doesn't decompile as prettily as XSE, but has a command line version. Both are Python based and need Python 3 and PIL (pip install pillow).
First I found the sewer in Advance Map and used XSE to view the script. I see checkitem 0x70, and if it isn't found, gripe about Safety Boots and the first time through, giveitem 0x71. So 70 is Safety Boots and 71 is the Jade Nugget I got. Now I know I need to find something that checks for 71 and gives 70.
I used Blue Spider to dump all maps: python dump_pks.py bonds.gba. This made a bunch of files and folders in map_dump. Then I did grep -r script_ptr map_dump to list all script addresses, and used sed to isolate the number and remove "0x8" from the start to go from a memory address to a file offset. I sorted and removed duplicates (sort|uniq), and dumped scripts at each of those addresses using Red Alien: cat offsets.txt | while read offs; do ./asc-cli d bonds.gba $offs > $offs.txt; done.
Now I can grep those scripts to find "checkitem 0x71" -- something that looks for Jade Nugget. I find it at 8ed4d0 so then I grep the dumped map files for that and find it in 3/map_4.pks, and reading the file tells me it's at 9,21 on it, which I can find in Advance Map.