Battle Logic Edits

Author(s): Lmaokai
Implementation & Research: HGSS Decompilation, Platinum Decompilation, HG Engine, Aero, Chritchy, DarmaniDan, Fantafaust, Lhea, Lmaokai, MeKomoATuPrima, Memory5ty7, MrHam88, Paille92, Shogo Kawada Fan, Yako

This page is a collation of hex edits to the battle logic in Generation IV Pokémon games. This primarily focuses on simpler aspects where only a single byte needs to be edited, such as Iron Fist's damage multiplier. Any hex editing offsets or files present on this page are for known good US versions of the relevant games.

These edits rely upon a basic understanding of hex editing and unpacking NARCs. An initial grounding in these subjects can be found in the following:

• Hex Editing Primer
• Unpacking NARCs

This information comes from tutorials, guides, and research shared via other means previously (within the Kingdom of DS Hacking! Discord server, pastebin, GitHub etc.), with some additional content and context added. Attribution should be given to the researchers and original tutorial writers, these are noted at the beginning of the relevant sections (and collectively at the top of this section).

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Table of Contents

• Statuses

  • Burn Damage
  • Paralysis Speed Reduction
  • Sleep Duration
  • Freeze Thaw Chance

• Abilities

  • Iron Fist Damage Multiplier
  • Pickup Activation Chance
  • Honey Gather Rate
  • Ice Body End-of-Turn HP Restoration
  • Heatproof Burn Damage Reduction
  • Quick Feet Speed Multiplier
  • Slow Start Stat-Reduction Duration
  • Rain Dish End-of-Turn HP Restoration
  • Reckless Damage Multiplier
  • Rivalry Damage Multipliers

• Items

  • Leftovers End-of-Turn HP Restoration
  • Black Sludge End-of-Turn HP Restoration
  • Black Sludge End-of-Turn Damage for Non-Poison Types
  • X Attack, X Defense, X Special, X Sp. Def, X Speed, and X Accuracy Stat Stage Boosts

• Move Effects

  • Aqua Ring End-of-Turn HP Restoration
  • Binding Moves End-of-Turn Damage
  • Binding Moves Duration
  • Magnitude Move Power
  • Gyro Ball Move Power Calculation Multiplier
  • Flail and Reversal Move Power

• Weather

  • Hail End-of-Turn Damage for Non-Ice Types
  • Remove Hail End-of-Turn Damage

• Miscellaneous

  • Critical Hit Rate

• Bug Fixes

  • Fire Fang vs Wonder Guard
  • Trainer AI Water Immunity Check vs Dry Skin

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Statuses

Burn Damage

Sources and Credits: DarmaniDan, HG Engine, Plat Decomp, HG Decomp

Unpack the relevant NARC, open the specified file, and change the byte at the provided offset:

Game	NARC to unpack	File	Offset	Vanilla Byte
HeartGold/SoulSilver	/a/0/0/1	1_26.bin	0x30	08
Platinum	/battle/skill/sub_seq.narc	sub_seq_26.bin	0x30	08
Diamond/Pearl	/battle/skill/sub_seq.narc	sub_seq_26.bin	0x30	08

Burn damage in Gen IV is 1/8^th of the Pokémon's max HP. The battle logic (more specifically, a battle subscript) calculates Burn damage by dividing the Pokémon's max HP by an explicitly defined value, in this case 8.

As an example, to change Burn damage from 1/8^th of the Pokémon's max HP to 1/16^th (matching Generation VII onwards), change the byte from 08 (8 in decimal) to 10 (16 in decimal). Make sure to pack the NARC after saving the file.

Paralysis Speed Reduction

Sources and Credits: Lmaokai, Plat Decomp (1, 2), HG Decomp (1, 2)

Open the relevant file and go to the provided offsets:

Game	File	Offset (Battler 1)	Vanilla Byte	Offset (Battler 2)	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x185CA	B6	0x18776	A4
Platinum	Overlay 16	0x17FCA	B6	0x18176	A4
Diamond/Pearl	Overlay 11	0x16EC6	B6	0x1702C	A4

You can also search for these bytes instead

	Battler 1	Battler 2
All Games	B6 08	A4 08

Paralysis in Gen IV decreases the Pokémon's Speed by 75%. Unfortunately, this is not achieved by simply dividing the Pokémon's Speed by 4. The battle logic calculates the decreased Speed by performing logical shifts. More specifically, the Pokémon's normal Speed is taken as a binary value, and those bits are shifted to the right by 2 bits, resulting in the same effect as dividing the value by 4.

To illustrate, take a Pokémon with 100 Speed. In binary, that is represented as 0110 0100. Shifting the bits to the right by 1 bit results in 0011 0010, or 50 in decimal. Shifting the bits to the right by 1 bit once again (for a total of 2 shifts) results in 0001 1001, or 25 in decimal.

We can change the number of logical shifts from 2 to 1, effectively changing the reduction from 75% to 50% (matching Gen VII and VIII). To do so, change the following bytes at the two offsets provided above:

Battler 1	Battler 2
B6 --> 76	A4 --> 64

Sleep Duration

Sources and Credits: Yako, Plat Decomp, HG Decomp, HG Engine

Unpack the relevant NARC, open the specified file, and change the byte(s) at the provided offset(s):

Game	NARC to unpack	File	Offset (Maximum Addend)	Vanilla Byte	Offset (Base # of Turns)	Vanilla Byte
HeartGold/SoulSilver	/a/0/0/1	1_18.bin	0x264	03	0x268	02
Platinum	/battle/skill/sub_seq.narc	sub_seq_18.bin	0x264	03	0x268	02
Diamond/Pearl	/battle/skill/sub_seq.narc	sub_seq_18.bin	0x250	03	0x254	02

Sleep in Gen IV lasts 2-5 turns, but effectively prevents movement for 1-4 turns. The battle logic (more specifically, a battle subscript) calculates the number of turns through the following process:

1. Generate a random number from zero to an explicitly defined value, in this case 3 (the 'Maximum Addend' or range)
2. Add it to another explicitly defined value, in this case 2 (the base number of turns)

This results in (0 + 2), (1 + 2), (2 + 2), and (3 + 2) as possible outcomes for the number of sleep turns, which effectively prevents movement for 1, 2, 3, or 4 turns.

As an example, for HeartGold/SoulSilver and Platinum, to change Sleep to instead last 2-4 turns, effectively preventing movement for 1-3 turns, (matching Gen V onwards), change the byte at 0x264 from 03 (3 in decimal) to 02 (2 in decimal). This results in (0 + 2), (1 + 2), (2 + 2), as possible outcomes, effectively preventing movement for 1, 2, or 3 turns. Make sure to pack the NARC after saving the file.

Freeze Thaw Chance

Sources and Credits: Plat Decomp, HG Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x13E12	05
Platinum	Overlay 16	0x137EE	05
Diamond/Pearl	Overlay 11	0x12998	05

You can also search for these bytes instead

Game	Bytes
HeartGold/SoulSilver	05 21 A7 F6
Platinum	05 21 93 F6
Diamond/Pearl	05 21 AB F6

A frozen Pokémon has a 20% chance of being thawed out on each of its turns in Gen IV. The battle logic calculates this chance through the following process:

1. Divide a random number by an explicitly defined value, in this case 5
2. Compare the remainder to 0
3. If the remainder is not equal to 0, the Pokémon remains frozen
4. If the remainder is equal to 0, then the Pokémon thaws out

Here is a table of bytes and the resulting thaw chance.

Byte	Resulting Thaw Chance
05	20% (Vanilla)
04	25%
03	33%
02	50%
01	100%

Abilities

Iron Fist Damage Multiplier

Sources and Credits: MrHam88, Yako, Plat Decomp, HG Decomp

Open the relevant file and change the byte(s) at the provided offset(s):

Game	File	Offset (Multiplier)	Vanilla Byte	Offset (Divisor)	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x1FF44	0C	0x1FF48	0A
Platinum	Overlay 16	0x1F94C	0C	0x1F950	0A
Diamond/Pearl	Overlay 11	0x1E520	0C	0x1E524	0A

You can also search for these bytes instead

	Vanilla Bytes
All Games	0C 20 60 43 0A 21

Iron Fist increases the power of effected punching moves by 20%. The battle logic calculates the increased damage by multiplying and dividing the move's power by explicitly defined values, in this case 12 and 10, respectively.

As an example, to change the boost from 20% to 50% (matching similar damage-boosting Abilities in later generations, such as Mega Launcher or Sharpness), change the byte at the multiplier offset from 0C (12 in decimal) to 0F (15 in decimal).

Pickup Activation Chance

Sources and Credits: Lhea, Aero, & DarmaniDan, Lmaokai, Plat Decomp, HG Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0xC852	0A
Platinum	Overlay 16	0xC62A	0A
Diamond/Pearl	Overlay 11	0xBCB2	0A

You can also search for these bytes instead

Game	Bytes
HeartGold/SoulSilver	0A 21 AE F6 40
Platinum	0A 21 9A F6 FE
Diamond/Pearl	0A 21 B2 F6 04

Pickup has a 10% activation chance. The battle logic calculates this chance through the following process:

1. Divide a random number by an explicitly defined value, in this case 10
2. Compare the remainder to 0
3. If the remainder is not equal to 0, then Pickup does not activate
4. If the remainder is equal to 0, then Pickup activates

Here is a table of bytes and the resulting Pickup activation chance.

Byte	Resulting Activation Chance
0A	10% (Vanilla)
09	11%
08	12.5%
07	14%
06	16.7%
05	20%
04	25%
03	33%
02	50%
01	100%

Honey Gather Rate

Sources and Credits: Lmaokai, DarmaniDan, Plat Decomp (1, 2), HG Decomp (1, 2)

Honey Gather has a variable activation chance, starting at 5% if the Pokémon is between levels 1-10, and increasing by 5% every 10 levels, ending at a 50% chance at levels 91-100.

The battle logic calculates this chance through the following process:

1. Get the Pokémon's level
2. Depending on the Pokémon's level, pull a specific value from the Honey Gather Rate Table (see below)
3. Divide a random number by an explicitly defined value, in this case 100
4. Compare the remainder to the value pulled from the Honey Gather Rate Table
5. If the remainder is greater than the value, then Honey Gather does not activate
6. If the remainder is less than the value, then Honey Gather activates

Honey Gather Rate Table

Levels	1-10	11-20	21-30	31-40	41-50	51-60	61-70	71-80	81-90	91-100
Value	5	10	15	20	25	30	35	40	45	50

Here are the offsets for the Honey Gather Rate Table:

Game	File	Offset
HeartGold/SoulSilver	Decompressed Overlay 12	0x35198
Platinum	Overlay 16	0x33974
Diamond/Pearl	Overlay 11	0x30B9C

You will see the following string of bytes that corresponds to the values of the Honey Gather Rate Table:

05 0A 0F 14 19 1E 23 28 2D 32

Given how the logic for Honey Gather works, the values in the table are effectively the literal rates for each level range respectively. As an example, if you wanted Honey Gather to have a 50% rate from levels 1-50, and a 100% rate from levels 51-100, then replace the ten bytes with the following:

32 32 32 32 32 64 64 64 64 64

Ice Body End-of-Turn HP Restoration

Sources and Credits: Lmaokai, DarmaniDan, Plat Decomp, HG Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0xA3F6	10
Platinum	Overlay 16	0xA1CE	10
Diamond/Pearl	Overlay 11	0x985E	10

You can also search for these bytes instead

Game	Bytes
HeartGold/SoulSilver	10 21 11 F0 5E
Platinum	10 21 11 F0 72
Diamond/Pearl	10 21 10 F0 4E

Ice Body restores 1/16^th of the Pokémon's max HP. The battle logic calculates the HP restoration amount by dividing the Pokémon's max HP by an explicitly defined value, in this case 16.

As an example, to change the HP restoration from 1/16^th of the Pokémon's max HP to 1/10^th, change the byte from 10 (16 in decimal) to 0A (10 in decimal).

Heatproof Burn Damage Reduction

Sources and Credits: Plat Decomp, HG Decomp

Unpack the relevant NARC, open the specified file, and change the byte at the provided offset:

Game	NARC to unpack	File	Offset	Vanilla Byte
HeartGold/SoulSilver	/a/0/0/1	1_26.bin	0x50	02
Platinum	/battle/skill/sub_seq.narc	sub_seq_26.bin	0x50	02
Diamond/Pearl	/battle/skill/sub_seq.narc	sub_seq_26.bin	0x50	02

Heatproof halves the normal damage done from the Burn status. The battle logic (more specifically, a battle subscript) calculates the reduced burn damage by dividing the normal burn damage by an explicitly defined value, in this case 2.

As an example, to change the divisor from 2 to 1 (effectively changing Heatproof to have no impact on burn damage), change the byte from 02 (2 in decimal) to 01 (1 in decimal). Alternatively, you can use a larger value to increase the reduction of burn damage (e.g. change the byte to 04 to divide the burn damage by 4). Make sure to pack the NARC after saving the file.

Quick Feet Speed Multiplier

Sources and Credits: Plat Decomp (1, 2), HG Decomp (1, 2)

Open the relevant file and go to the provided offsets:

Game	File	Offset (Battler 1 Multiplier)	Vanilla Byte	Offset (Battler 1 Divisor)	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x185AE	0F	0x185B2	0A
Platinum	Overlay 16	0x17FAE	0F	0x17FB2	0A
Diamond/Pearl	Overlay 11	0x16EAA	0F	0x16EAE	0A

Game	File	Offset (Battler 2 Multiplier)	Vanilla Byte	Offset (Battler 2 Divisor)	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x1875A	0F	0x1875E	0A
Platinum	Overlay 16	0x1815A	0F	0x1815E	0A
Diamond/Pearl	Overlay 11	0x17010	0F	0x17014	0A

You can also search for these bytes instead

Game	Battler 1	Battler 2
HeartGold/SoulSilver	0F 20 70 43 0A 21 A2 F6 96	0F 20 60 43 0A 21 A2 F6 C0
Platinum	0F 20 70 43 0A 21 8F F6 40	0F 20 60 43 0A 21 8E F6 6A
Diamond/Pearl	0F 20 70 43 0A 21 A7 F6 0C	0F 20 60 43 0A 21 A7 F6 5A

Quick Feet increases the Pokémon's Speed by 50%. The battle logic calculates the increased Speed by multiplying and dividing the Pokémon's Speed by explicitly defined values, in this case 15 and 10, respectively.

As an example, to change the boost from 50% to 70%, change the byte at the multiplier offsets for both battlers from 0F (15 in decimal) to 11 (17 in decimal).

Slow Start Stat-Reduction Duration

Sources and Credits: Chritchy, Plat Decomp (1, 2, 3, 4), HG Decomp (1, 2, 3, 4)

Open the relevant file and change the bytes at the provided offsets:

Game	File	Offset 1	Offset 2	Offset 3	Offset 4	Vanilla Byte (All Offsets)
HeartGold/SoulSilver	Decompressed Overlay 12	0x185E2	0x1878E	0x1C2A8	0x1FA38	05
Platinum	Overlay 16	0x17FE2	0x1818E	0x1BCB0	0x1F440	05
Diamond/Pearl	Overlay 11	0x16EDE	0x17044	0x1AAA8	0x1E050	05

You can also search for these bytes instead

	Offset 1	Offset 2	Offset 3	Offset 4
All Games	05 28 00 DA 76	05 28 00 DA 64	05 28 0D	05 28 03

Slow Start lasts for 5 turns whenever the Pokémon is switched into battle. As an example, to change the duration from 5 turns to 4, go to each offset listed and change the byte from 05 (5 in decimal) to 04 (4 in decimal).

Rain Dish End-of-Turn HP Restoration

Sources and Credits: Lhea, Plat Decomp, HG Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0xA46C	10
Platinum	Overlay 16	0xA244	10
Diamond/Pearl	Overlay 11	0x98D4	10

You can also search for these bytes instead

	Vanilla Bytes
All Games	10 21 80 59

Rain Dish restores 1/16^th of the Pokémon's max HP. The battle logic calculates the HP restoration amount by dividing the Pokémon's max HP by an explicitly defined value, in this case 16.

As an example, to change the HP restoration from 1/16^th of the Pokémon's max HP to 1/10^th, change the byte from 10 (16 in decimal) to 0A (10 in decimal).

Reckless Damage Multiplier

Sources and Credits: Yako, Plat Decomp (1, 2, 3, 4, 5, 6), HGSS Decomp (1, 2, 3, 4, 5, 6)

Reckless increases the power of moves that have recoil or crash damage by 20%, except Struggle. The battle logic (more specifically, multiple move effect scripts) calculates the increased damage by multiplying the move's power by an explicitly defined value, in this case 12.

The multiplier value is explicitly defined across six individual move effect scripts that involve recoil or crash damage in the vanilla Pokémon games. This means six edits are required to effectively change Reckless' damage multiplier.

The divisor value is explicitly defined in the general battle logic overlay (i.e. Overlay 12 for HeartGold/SoulSilver, Overlay 16 for Platinum, and Overlay 11 for Diamond/Pearl), but is a general-use function that handles every case in which a move's power is modified.

Unpack the following NARCs, open the six specified files, and change the bytes at the provided offsets. Make sure to pack the NARC after saving all the files.

1) Move Effect Script 45: Crash Damage if Move Misses (Hi Jump Kick, Jump Kick)

Game	NARC to unpack	File	Offset	Vanilla Byte
HeartGold/SoulSilver	/a/0/3/0	0_45.bin	0x20	0C
Platinum	/battle/skill/be_seq.narc	be_seq_45.bin	0x20	0C
Diamond/Pearl	/battle/skill/be_seq.narc	be_seq_45.bin	0x20	0C

2) Move Effect Script 48: 25% Recoil Damage (Take Down, Submission)

Game	NARC to unpack	File	Offset	Vanilla Byte
HeartGold/SoulSilver	/a/0/3/0	0_48.bin	0x20	0C
Platinum	/battle/skill/be_seq.narc	be_seq_48.bin	0x20	0C
Diamond/Pearl	/battle/skill/be_seq.narc	be_seq_48.bin	0x20	0C

3) Move Effect Script 198: 33% Recoil Damage (Double-Edge, Brave Bird, Wood Hammer)

Game	NARC to unpack	File	Offset	Vanilla Byte
HeartGold/SoulSilver	/a/0/3/0	0_198.bin	0x20	0C
Platinum	/battle/skill/be_seq.narc	be_seq_198.bin	0x20	0C
Diamond/Pearl	/battle/skill/be_seq.narc	be_seq_198.bin	0x20	0C

4) Move Effect Script 253: 33% Recoil Damage, Chance to Burn, and Thaws the User (Flare Blitz)

Game	NARC to unpack	File	Offset	Vanilla Byte
HeartGold/SoulSilver	/a/0/3/0	0_253.bin	0x20	0C
Platinum	/battle/skill/be_seq.narc	be_seq_253.bin	0x20	0C
Diamond/Pearl	/battle/skill/be_seq.narc	be_seq_253.bin	0x20	0C

5) Move Effect Script 262: 33% Recoil Damage and Chance to Paralyze (Volt Tackle)

Game	NARC to unpack	File	Offset	Vanilla Byte
HeartGold/SoulSilver	/a/0/3/0	0_262.bin	0x20	0C
Platinum	/battle/skill/be_seq.narc	be_seq_262.bin	0x20	0C
Diamond/Pearl	/battle/skill/be_seq.narc	be_seq_262.bin	0x20	0C

6) Move Effect Script 269: 50% Recoil Damage (Head Smash)

Game	NARC to unpack	File	Offset	Vanilla Byte
HeartGold/SoulSilver	/a/0/3/0	0_269.bin	0x20	0C
Platinum	/battle/skill/be_seq.narc	be_seq_269.bin	0x20	0C
Diamond/Pearl	/battle/skill/be_seq.narc	be_seq_269.bin	0x20	0C

Rivalry Damage Multipliers

Sources and Credits: MeKomoATuPrima, Plat Decomp, HG Decomp

Open the relevant file and go to the provided offsets:

Game	File	Offset (Same Gender Multiplier)	Vanilla Byte	Offset (Same Gender Divisor)	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x1FF00	7D	0x1FF04	64
Platinum	Overlay 16	0x1F908	7D	0x1F90C	64
Diamond/Pearl	Overlay 11	0x1E4DC	7D	0x1E4E0	64

Game	File	Offset (Opposite Gender Multiplier)	Vanilla Byte	Offset (Opposite Gender Divisor)	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x1FF26	4B	0x1FF2A	64
Platinum	Overlay 16	0x1F92E	4B	0x1F932	64
Diamond/Pearl	Overlay 11	0x1E502	4B	0x1E506	64

You can also search for these bytes instead

Game	Same Gender	Opposite Gender
HeartGold/SoulSilver	7D 20 60 43 64 21 9B F6 E8	4B 20 60 43 64
Platinum	7D 20 60 43 64 21 87 F6 8E	4B 20 60 43 64
Diamond/Pearl	7D 20 60 43 64 21 A0 F6 EE	4B 20 60 43 64

Rivalry increases the power of moves by 25% if the target and the user have the same gender. The battle logic calculates the increased damage by multiplying and dividing the move's power by explicitly defined values, in this case 125 (7D in hexadecimal) and 100 (64 in hexadecimal), respectively.

Rivalry reduces the power of moves by 25% if the target and the user have opposite genders. The battle logic calculates the reduced damage by multiplying and dividing the move's power by explicitly defined values, in this case 75 (4B in hexadecimal) and 100 (64 in hexadecimal), respectively.

Items

Leftovers End-of-Turn HP Restoration

Sources and Credits: Lhea, Plat Decomp, HG Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset (Leftovers)	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x1D508	10
Platinum	Overlay 16	0x1CF10	10
Diamond/Pearl	Overlay 11	0x1BD2C	10

You can also search for these bytes instead

Game	Bytes
HeartGold/SoulSilver	10 21 FE F7 D5
Platinum	10 21 FE F7 D1
Diamond/Pearl	10 21 FE F7 E7

Leftovers (specifically the item held effect assigned to Leftovers in vanilla Pokémon games) restores 1/16^th of the Pokémon's max HP. HP restoration for this item held effect is determined in the battle logic instead of the item's properties (meaning changing those values in DSPRE's Item Editor has no impact), and is calculated by dividing the Pokémon's max HP by an explicitly defined value, in this case 16.

As an example, to change end-of-turn HP restoration from 1/16^th of the Pokémon's max HP to a whopping 1/2^th (for testing purposes, of course), change the byte from 10 (16 in decimal) to 02 (2 in decimal).

Black Sludge End-of-Turn HP Restoration

Sources and Credits: Lhea, Plat Decomp, HG Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset (Black Sludge)	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x1D548	10
Platinum	Overlay 16	0x1CF50	10
Diamond/Pearl	Overlay 11	0x1BD6C	10

You can also search for these bytes instead

Game	Bytes
HeartGold/SoulSilver	10 21 FE F7 B5
Platinum	10 21 FE F7 B1
Diamond/Pearl	10 21 FE F7 C7

Black Sludge (specifically the item held effect assigned to Black Sludge in vanilla Pokémon games) restores 1/16^th of a Poison-Type Pokémon's max HP. HP restoration for this item held effect is determined in the battle logic instead of the item's properties (meaning changing those values in DSPRE's Item Editor has no impact), and is calculated by dividing the Pokémon's max HP by an explicitly defined value, in this case 16.

As an example, to change end-of-turn HP restoration from 1/16^th of the Pokémon's max HP to 1/10^th, change the byte from 10 (16 in decimal) to 0A (10 in decimal).

Black Sludge End-of-Turn Damage for Non-Poison Types

Sources and Credits: Lhea, Plat Decomp, HG Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x1D570	08
Platinum	Overlay 16	0x1CF78	08
Diamond/Pearl	Overlay 11	0x1BD94	08

You can also search for these bytes instead

	Vanilla Bytes
All Games	08 21 FE F7

Black Sludge (specifically the item held effect assigned to Black Sludge in vanilla Pokémon games) damages 1/8^th of a non-Poison-Type Pokémon's max HP. Damage for this item held effect is determined in the battle logic instead of the item's properties, and is calculated by dividing the Pokémon's max HP by an explicitly defined value, in this case 8.

As an example, to change the end-of-turn damage from 1/8^th of the Pokémon's max HP to 1/16^th, change the byte from 08 (8 in decimal) to 10 (16 in decimal).

X Attack, X Defense, X Special, X Sp. Def, X Speed, and X Accuracy Stat Stage Boosts

Sources and Credits: Plat Decomp, HG Decomp

Open the relevant file and go to the provided offsets:

Game	File	Offset (X Attack)	Offset (X Defense)	Offset (X Special)	Offset (X Sp. Def)	Offset (X Speed)	Offset (X Accuracy)	Vanilla Byte (All Offsets)
HeartGold/SoulSilver	Decompressed Overlay 12	0x372A	0x3768	0x37A6	0x37E4	0x3822	0x3860	01
Platinum	Overlay 16	0x3596	0x35D4	0x3612	0x3650	0x368E	0x36CC	01
Diamond/Pearl	Overlay 11	0x317A	0x31B8	0x31F6	0x3234	0x3272	0x32B0	01

You can also search for these bytes instead

Game	Bytes (6 results)
HeartGold/SoulSilver	01 23 14 F0
Platinum	01 23 14 F0
Diamond/Pearl	01 23 13 F0

The item properties assigned to X Attack, X Defense, X Special, X Sp. Def, X Speed, and X Accuracy in Gen IV enable them to be used from the bag during battle to raise the Pokémon's respective stat by 1 stage.

As an example, to change the effect to raise the Pokémon's respective state by 2 stages (matching Gen VII onwards), change the byte from 01 to 02.

Move Effects

Aqua Ring End-of-Turn HP Restoration

Sources and Credits: Lhea, Fantafaust, Lmaokai, Plat Decomp, HG Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x1257A	10
Platinum	Overlay 16	0x11FB2	10
Diamond/Pearl	Overlay 11	0x11252	10

You can also search for these bytes instead

Game	Bytes
HeartGold/SoulSilver	10 21 09 F0 9C
Platinum	10 21 09 F0 80
Diamond/Pearl	10 21 08 F0 54

The move effect assigned to Aqua Ring restores 1/16^th of the Pokémon's max HP. The battle logic calculates the HP restoration amount for this move effect by dividing the Pokémon's max HP by an explicitly defined value, in this case 16.

As an example, to change the HP restoration from 1/16^th of the Pokémon's max HP to 1/10^th, change the byte from 10 (16 in decimal) to 0A (10 in decimal).

Binding Moves End-of-Turn Damage

Sources and Credits: MrHam88, Lhea, Paille92, Lmaokai, Plat Decomp, HG Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x12852	10
Platinum	Overlay 16	0x1228A	10
Diamond/Pearl	Overlay 11	0x11528	10

You can also search for these bytes instead

Game	Bytes
HeartGold/SoulSilver	10 21 09 F0 30
Platinum	10 21 09 F0 14
Diamond/Pearl	10 21 08 F0 E9

The move effect assigned to binding moves such as Bind, Fire Spin, and Whirlpool, deals 1/16^th of the Pokémon's max HP. The battle logic calculates the damage for this move effect by dividing the Pokémon's max HP by an explicitly defined value, in this case 16.

As an example, to change the damage from 1/16^th of the Pokémon's max HP to 1/8^th (matching Gen VI onwards), change the byte from 10 (16 in decimal) to 08 (8 in decimal).

Binding Moves Duration

Sources and Credits: MrHam88, Yako & DarmaniDan, Plat Decomp, HG Decomp

Unpack the relevant NARC, open the specified file, and change the byte(s) at the provided offset(s):

Game	NARC to unpack	File	Offset (Maximum Addend)	Vanilla Byte	Offset (Base # of Turns)	Vanilla Byte
HeartGold/SoulSilver	/a/0/0/1	1_58.bin	0x38	03	0x3C	03
Platinum	/battle/skill/sub_seq.narc	sub_seq_58.bin	0x38	03	0x3C	03
Diamond/Pearl	/battle/skill/sub_seq.narc	sub_seq_58.bin	0x38	03	0x3C	03

The move effect assigned to binding moves such as Bind, Fire Spin, and Whirlpool, lasts 3-6 turns in Gen IV, but effectively traps and deals damage for 2-5 turns. The battle logic (more specifically, a battle subscript) calculates the total number of turns through the following process:

1. Generate a random number from zero to an explicitly defined value, in this case 3 (the 'Maximum Addend' or range)
2. Add it to another explicitly defined value, in this case 3 (the base number of turns)

This results in (0 + 3), (1 + 3), (2 + 3), and (3 + 3) as possible outcomes for the number of turns, which effectively traps and deals damage for 2, 3, 4, or 5 turns.

As an example, to change the duration to instead last 5-6 turns (effectively lasting for 4-5 turns, matching Gen V onwards)

1. Change the byte at 0x38 from 3 (3 in decimal) to 01 (1 in decimal)
2. Change the byte at 0x3C from 3 (3 in decimal) to 05 (5 in decimal)

This results in (0 + 5) and (1 + 5) as possible outcomes, effectively lasting for 4 or 5 turns. Make sure to pack the NARC after saving the file.

Another example, but to fix the duration to always be 3 effective turns

1. Change the byte at 0x38 from 3 (3 in decimal) to 00 (0 in decimal)
2. Change the byte at 0x3C from 3 (3 in decimal) to 04 (4 in decimal)

Later in the same file contains the logic for Grip Claw (specifically the item held effect assigned to Grip Claw in vanilla Pokémon games) causing binding moves to always last a certain number of turns.

Game	Offset (Grip Claw Duration)	Vanilla Byte
HeartGold/SoulSilver	0x60	06
Platinum	0x60	06
Diamond/Pearl	0x60	06

As an example, to change Grip Claw to cause binding moves to always last for 6 effective turns, change the byte at 0x60 from 06 (6 in decimal) to 07 (7 in decimal). Make sure to pack the NARC after saving the file.

warning

The forced Grip Claw duration cannot be changed to a value greater than 07.

Magnitude Move Power

Sources and Credits: Plat Decomp (1, 2), HG Decomp (1, 2)

Open the relevant file and go to the provided offsets:

Game	File	Offset (Magnitude 4)	Vanilla Byte	Offset (Magnitude 5)	Vanilla Byte	Offset (Magnitude 6)	Vanilla Byte	Offset (Magnitude 7)	Vanilla Byte	Offset (Magnitude 8)	Vanilla Byte	Offset (Magnitude 9)	Vanilla Byte	Offset (Magnitude 10)	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0xA89A	0A	0xA8AA	1E	0xA8BA	32	0xA8CA	46	0xA8DA	5A	0xA8EA	6E	0xA8F4	96
Platinum	Overlay 16	0xA672	0A	0xA682	1E	0xA692	32	0xA6A2	46	0xA6B2	5A	0xA6C2	6E	0xA6CC	96
Diamond/Pearl	Overlay 11	0x9CFA	0A	0x9D0A	1E	0x9D1A	32	0x9D2A	46	0x9D3A	5A	0x9D4A	6E	0x9D54	96

You can also search for these bytes instead

	Magnitude 4 Bytes	Magnitude 5 Bytes	Magnitude 6 Bytes	Magnitude 7 Bytes	Magnitude 8 Bytes	Magnitude 9 Bytes	Magnitude 10 Bytes
All Games	0A 22 62	1E 22 62	32 22 62	46 22 62	5A 22 62	6E 22 62	96 22 62

The move effect assigned to Magnitude has a varying move power based on randomly selected "magnitude" level. The battle logic first determines the "magnitude" level, then provides the explicitly defined move power associated with each "magnitude" level.

Magnitude Level	Vanilla Power	Vanilla Byte
4	10	0A
5	30	1E
6	50	32
7	70	46
8	90	5A
9	110	6E
10	150	96

Additionally, the trainer AI may simulate a Magnitude roll depending on assigned AI flags. This is handled in a different overlay with a separate set of explicitly defined values.

Game	File	Offset (Magnitude 4)	Offset (Magnitude 5)	Offset (Magnitude 6)	Offset (Magnitude 7)	Offset (Magnitude 8)	Offset (Magnitude 9)	Offset (Magnitude 10)
HeartGold/SoulSilver	Decompressed Overlay 10	0x351C	0x3524	0x352C	0x3534	0x353C	0x3544	0x3548
Platinum	Overlay 14	0x351C	0x3524	0x352C	0x3534	0x353C	0x3544	0x3548
Diamond/Pearl	Overlay 16	0x1BCBC	0x1BCC4	0x1BCCC	0x1BCD4	0x1BCDC	0x1BCE4	0x1BCE8

You can also search for these bytes instead

	Magnitude 4 Bytes	Magnitude 5 Bytes	Magnitude 6 Bytes	Magnitude 7 Bytes	Magnitude 8 Bytes	Magnitude 9 Bytes	Magnitude 10 Bytes
All Games	0A 24 14 E0	1E 24 10 E0	32 24 0C E0	46 24 08 E0	5A 24 04 E0	6E 24 00 E0	96 24 00 27 22

Gyro Ball Move Power Calculation Multiplier

Sources and Credits: Plat Decomp (1, 2), HG Decomp (1, 2)

Open the relevant file and go to the provided offsets:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0xBEAA	19
Platinum	Overlay 16	0xBC82	19
Diamond/Pearl	Overlay 11	0xB316	19

You can also search for these bytes instead

	Bytes
All Games	19 20 50

The move effect assigned to Gyro Ball has a varying move power based on the user's Speed compared to the target's Speed. The battle logic calculates the move's power by dividing the target's Speed by the user's Speed, then multiplying the result by an explicitly defined value, in this case 25 (19 in hexadecimal). Increasing this value will increase the calculated power (but is still restricted by the maximum power cap of 150).

Additionally, the trainer AI may calculate Gyro Ball's power depending on assigned AI flags. This is handled in a different overlay.

Game	File	Offset
HeartGold/SoulSilver	Decompressed Overlay 10	0x347C
Platinum	Overlay 14	0x347C
Diamond/Pearl	Overlay 16	0x1BC20

Flail and Reversal Move Power

Sources and Credits: Plat Decomp (1, 2), HG Decomp (1, 2)

The move effect assigned to Flail and Reversal has a varying move power based on the user's current HP compared to its max HP. The battle logic calculates the move's power in two parts. First, the user's current HP is divided by its max HP, then multiplied by an explicitly defined value, in this case 64 (40 in hexadecimal). Second, the result is compared to a table that provides an explicitly defined move power.

From Gen V onwards, the multiplier was changed from 64 to 48, with the ratios likely changed as well (see Pokemon Database for Gen V+ ratios).

If you change the multiplier in the initial calculation, you will need to change the ratio(s) in the table. Otherwise, the intended move power may not be returned.

Flail/Reversal Calculation Multiplier

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x97A4	40
Platinum	Overlay 16	0x957C	40
Diamond/Pearl	Overlay 11	0x8C18	40

You can also search for these bytes instead

Game	Bytes
HeartGold/SoulSilver	40 22 26
Platinum	40 22 47
Diamond/Pearl	40 22 43

Flail/Reversal Power Table

Open the relevant file and go the provided offset:

Game	File	Offset
HeartGold/SoulSilver	Decompressed Overlay 12	0x34A40
Platinum	Overlay 16	0x33444
Diamond/Pearl	Overlay 11	0x3067C

	Vanilla Bytes
All Games	01 C8 05 96 0C 64 15 50 2A 28 40 14

Here is the table of the HP ratio (based on the vanilla multiplier of 64) to Move Power.

Ratio (N)	Vanilla Byte	Move Power	Vanilla Byte
N ≤ 1	01	200	C8
1 < N ≤ 5	05	150	96
5 < N ≤ 12	0C	100	64
12 < N ≤ 21	15	80	50
21 < N ≤ 42	2A	40	28
42 < N ≤ 64	40	20	14

Weather

Hail End-of-Turn Damage for Non-Ice Types

Sources and Credits: Lmaokai, Plat Decomp, HG Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0xA42C	10
Platinum	Overlay 16	0xA204	10
Diamond/Pearl	Overlay 11	0x9894	10

You can also search for these bytes instead

Game	Bytes
HeartGold/SoulSilver	10 21 11 F0 43
Platinum	10 21 11 F0 57
Diamond/Pearl	10 21 10 F0 33

Hail damages 1/16^th of a non-Ice-Type Pokémon's max HP. The battle logic calculates this damage by dividing the Pokémon's max HP by an explicitly defined value, in this case 16.

As an example, to change Hail damage from 1/16^th of the Pokémon's max HP to 1/12^th, change the byte from 10 (16 in decimal) to 0C (12 in decimal).

Remove Hail End-of-Turn Damage

Sources and Credits: Plat Decomp, HG Decomp

Open the relevant file and go to the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0xA406	16 D0
Platinum	Overlay 16	0xA1DE	16 D0
Diamond/Pearl	Overlay 11	0x986E	16 D0

You can also search for these bytes instead

	Bytes
All Games	16 D0 0F 2F

At this location, the battle logic checks if the Pokémon's first type is Ice, then if the second type is Ice, then if the ability is Snow Cloak to skip applying Hail damage to the Pokémon. Replacing 16 D0 with 16 E0 at this offset changes the first check from a conditional branch to an unconditional branch, which will effectively skip applying Hail damage to all Pokémon (mirroring the Snow weather that replaces Hail in Gen IX onwards).

Miscellaneous

Critical Hit Rate

Sources and Credits: Lhea, Plat Decomp, HG Decomp

Open the relevant file and go to the provided offset:

Game	File	Offset
HeartGold/SoulSilver	Decompressed Overlay 12	0x35288
Platinum	Overlay 16	0x33A60
Diamond/Pearl	Overlay 11	0x30C84

The battle logic calculates the chance of a critical hit by using a certain value as a divisor, pulled from a table based on the Pokémon's critical hit ratio stage. For example, in Gen IV, if an attacking Pokémon has a critical hit ratio stage of +2, then the chance of a critical hit rate is 1/4.

Here is a table of the vanilla bytes, as well as bytes that match the changes in Gen VI and Gen VII onwards.

	Bytes	Resulting Critical Hit Chance per Stage
Gen IV	10 08 04 03 02	[1/16] [1/8] [1/4] [1/3] [1/2]
Gen VI	10 08 02 01 01	[1/16] [1/8] [1/2] [1] [1]
Gen VII+	18 08 02 01 01	[1/24] [1/8] [1/2] [1] [1]

Bug Fixes

Fire Fang vs Wonder Guard

Sources and Credits: Lhea, Shogo Kawada Fan

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 12	0x20BCC	11
Platinum	Overlay 16	0x205D4	11
Diamond/Pearl	Overlay 11	0x1F160	11

You can also search for these bytes instead

	Vanilla Bytes
All Games	11 32 93 42

Fire Fang (specifically the move effect assigned to only Fire Fang) is able to hit through Wonder Guard, even if the target does not have a weakness to Fire-Type moves. More information about the bug can be found on Bulbapedia or searching Fire Fang Wonder Guard on the Kingdom of DS Hacking Discord.

To fix the issue, change the byte from 11 to 10.

Trainer AI Water Immunity Check vs Dry Skin

Sources and Credits: Memory5ty7, DarmaniDan, Lhea, Plat Decomp

Open the relevant file and change the byte at the provided offset:

Game	File	Offset	Vanilla Byte
HeartGold/SoulSilver	Decompressed Overlay 10	0x4DB4	1A
Platinum	Overlay 14	0x4DAC	1A
Diamond/Pearl	Overlay 16	0x1DA7C	1A

You can also search for these bytes instead

	Vanilla Bytes
All Games	1A 00 00 00 26 00 00 00

The Trainer AI performs two checks when considering whether the opposing Pokémon is immune to Water-Type moves. The first check considers Water Absorb, but the second check mistakenly considers Levitate instead of Dry Skin. In practice, this means that (1) a Trainer's Pokémon won't use Water-Type moves if it knows that the opposing Pokémon has Levitate, and (2) a Trainer's Pokémon may repeatedly use a Water-Type move against an opposing Pokémon with Dry Skin.

To fix the issue, change the byte from 1A (26 in decimal, Levitate's ID) to 57 (87 in decimal, Dry Skin's ID).