User:Mugendai

Hello, you may call me Mugendai. I'm a longtime Animal Crossing fan; I bought the original Gamecube game in 2002 or 2003. Now I've been hacking the ACGC town save file, having already cracked the checksum and successfully edited the items in my inventory and on the acres. Hopefully there will finally be a map editor for the original Animal Crossing. 10 years and there still hasn't been a map editor for the best Animal Crossing game! Can you believe it?!

How to bypass the ACGC save file checksum
In the GCI file, there are two copies of the town save file; one at 0x26040 and the other at 0x4C040. If the first one only has an invalid checksum, the game loads the town from the second copy. If both copies have an invalid checksum, K.K. Slider appears after you press start and solemnly tells you that your town is corrupted.

You only need to fix the checksum in the first copy of the save for it to work, and the game always loads from the first copy if it's correct. The checksumming works like this: add all 16-bit values from 0x26040 to 0x4C03F inclusively. The result is a 16-bit value; the number wraps around if it goes over 0xFFFF. The final 16-bit value must equal 0x0000, otherwise the copy is corrupted.

The 16-bit checksum value that offsets the rest of the values is at 0x26052. It is big-endian, like the rest of the values in the save. You would change this value to make the entire copy equal 0x0000, after making whatever edits you like to the copy itself. Hopefully I explained this clearly enough. Here's a Python script to automatically fix the checksum for you: http://pastebin.com/QTfd6rDp

List of Animal Crossing beta items that look like the DUMMY

 * 1224 - kagamimochi
 * 1240 - heavy chair
 * 1244 - school chair
 * 1248 - towel chair
 * 1250 - stepstool
 * 12F0 - unused dresser
 * 1314 - unused monkey
 * 1344 - modern den chair
 * 13F8 - giant dharma
 * 13FC - dharma
 * 1400 - mini-dharma
 * 1418 - striped cone
 * 1420 - cola machine
 * 1430 - barricade
 * 1434 - fence
 * 1438 - plastic fence
 * 143C - fence and sign
 * 144C - brown drum
 * 1454 - red drum
 * 1458 - juice machine
 * 1464 - garbage pail
 * 1474 - robotic flagman
 * 1490 - zen basin
 * 1498 - wash basin
 * 1460 - trash can
 * 14A0 - warning sign
 * 14B0 - route sign
 * 14B4 - men working sign
 * 14B8 - caution sign
 * 14BC - temple basin
 * 14CC - unused chair
 * 1520 - bucket
 * 1528 - faucet
 * 152C - spa chair
 * 1548 - massage chair
 * 154C - bath mat
 * 1550 - spa tub
 * 1564 - clerk's booth
 * 1574 - spa screen
 * 1594 - bath locker
 * 1598 - milk fridge
 * 1E74 - lucky cat
 * 1E78 - lucky black cat
 * 1E80 - racoon obje
 * 1E84 - lucky frog
 * 1EDC - alcove
 * 1EE0 - hearth
 * 3038 - moon dumpling
 * 303C - bean set
 * 3040 - osechi
 * 3058 - spring medal
 * 305C - fall medal
 * 3068 - long-life noodle
 * 306C - bass boat
 * 308C - mortar ball
 * 3098 - big catch flag
 * 31BC - hibachi grill
 * 31D8 - scary painting
 * 31DC - novel painting
 * 321C - golf trophy
 * 3228 - tennis trophy
 * 3230 - kart trophy
 * 32C0 - western fence