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Save data structure in Generation IV

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The save data structure in the Nintendo DS is stored as a .SAV file, which is broken up into two pairs of blocks. Each pair has one small block, and one big block. The offsets for Platinum are different from Diamond and Pearl.

In Diamond and Pearl, the first small block starts at 0x00000 and ends at 0x0C0FF, the first big block starts at 0x0C100 and ends at 0x1E2DF. In Platinum, the first small block starts at 0x00000 and ends at 0x0CF2B, the first big block starts at 0x0CF2C and ends at 0x1F10F. The second pair of blocks are at the same address plus 0x40000 for all the three games.

One block pair is always a backup of the other block pair.

Small block

The small block has the following data:

Offset Contents
0x68 - 0x77 Trainer Name
0x78 - 0x79 Trainer ID
0x7A - 0x7B Secret ID
0x7C - 0x7F Money
0x80 Gender
0x81 Origin
0x82 Badges
0x83 Avatar
0x9C Number of Pokémon in Party
0xA0 - 0x627 Party Pokémon blocks
0x00630 - 0x008C3 Items placeholder
0x008C4 - 0x0098B Key Items placeholder
0x0098C - 0x00B4B TMs & HMs placeholder
0x00B4C - 0x00BEB Medicines placeholder
0x00BDC - 0x00CEB Berries placeholder
0x00CEC - 0x00D27 Poké Balls placeholder
0x00D28 - 0x00D5B Battle Items placeholder
0x00D5C - 0x00D8B Mail placeholder
0x0CF18 - 0x0CF2B Footer

Item placeholders

In these placeholders, each item takes 4 bytes with the following structure:

Offset Contents
0x00 - 0x01 Item ID
0x02 - 0x03 Item amount

Each item has a unique ID to get identified. See the list of items by index number (Generation IV) for these IDs.

Footer

The last 0x14 bytes of each block (small and big) are used as a footer. It has the following structure:

Offset Contents
0x00 - 0x03 Used to connect a small block with a big block
0x04 - 0x07 Number of the save
0x08 - 0x0B Size of the block
0x0C - 0x0F K
0x10 - 0x11 T
0x12 - 0x13 Checksum of the block

Checksum

The game uses a CRC-16-CCITT algorithm for the checksums. These checksums are calculated from a whole block without taking the footer.

Example

SMALL BLOCK 1
D1 01 00 00 | 42 04 00 00 | 00 C1 00 00 | 23 06 06 20 | 00 00 | 7E 7A

BIG BLOCK 1
D0 01 00 00 | F1 02 00 00 | E0 21 01 00 | 23 06 06 20 | 01 00 | 0D 39
SMALL BLOCK 2
D0 01 00 00 | 41 04 00 00 | 00 C1 00 00 | 23 06 06 20 | 00 00 | 0C 7F

BIG BLOCK 2
D1 01 00 00 | F2 02 00 00 | E0 21 01 00 | 23 06 06 20 | 01 00 | F6 8A

Since the value of 0x0C0F0 - 0x0C0F3 is higher in small block 1 (42 04 00 00 > 41 04 00 00), that is the current small block. Then, by matching the value of 0x0C0EC - 0x0C0EF (which is D1 01 00 00) to the big block. This means that the current big block is actually big block 2 (assuming the big block's checksum is correct).


Data structure in the Pokémon games
Generation I Pokémon data structurePokémon base stats data structureSave data structure
Generation II Pokémon data structurePokémon base stats data structureTrainer data structureSave data structure
Generation III Pokémon data structurePokémon data substructuresPokémon base stats data structureMove data structure
Contest data structureContest move data structureItem data structurePokédex data structureBattle Frontier data structures
Trainer Tower data structuresPokémon evolution data structureType Chart data structureSave data structure
Generation IV Pokémon data structureSave data structure

Project Games logo.png This data structure article is part of Project Games, a Bulbapedia project that aims to write comprehensive articles on the Pokémon games.