Pokémon cloning (Generation II)

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Major glitches of the Pokémon series

Arbitrary code execution

0x1500 control code arbitrary code execution (Crystal) | Cart-swap arbitrary code execution | Generation I custom map script pointer | Generation I invalid meta-map scripts | Generation I item ("8F", "ws m", "-g m", "5かい", "てへ" etc.) | Generation I move ("-", "TM42") | Generation I Trainer escape glitch text boxes | Generation II bad clone | Generation II Burned Tower Silver | Japanese Crystal Pokémon Communication Center SRAM glitches | Coin Case glitch | Generation II glitch Pokédex sortings | Pikachu off-screen glitch ACE | OAM DMA hijacking | Pikachu glitch emote | Generation III glitch Pokémon summary | Generation III glitch move animation) | Remote code execution | TM/HMs outside of the TM/HM pocket | ZZAZZ glitch Trainer FC

No further extensions

Cloning | Item duplication glitch (Generation I) | Pokémon merge glitch ("Q Glitch", Generation I) | Time Capsule exploit | Bug-Catching Contest data copy glitch (Generation II, Japan only) | Berry glitch | Battle Tower Lati@s glitch (Generation III) | (Mimic) Transform Rage glitch (Generation IV)

Transform held item glitch (Generation IV, Japan only) | Mimic glitch (Generation IV, Japan only)

Buffer overflow techniques

99 item stack glitch | LOL glitch | Rival LOL glitch | Instant LOL glitch | RAM LOL glitch | Out of bounds LOL glitch | blockoobLG | Instant encounter infinite chain glitch | LGFly | Super Glitch (Generation I) | Party remaining HP glitch | Super Glitch (Generation III) | Text pointer manipulation mart buffer overflow glitch | CoolTrainer♀-type move | Double distort CoolTrainer♀ corruption | Yami Shop glitch | Party Pokémon box data shift glitch | Unterminated name glitch item instant encounter (Japanese Red/Green)

Item stack duplication glitch (Generation I)

Generation I expanded items pack (Glitch Rocket HQ maps, Map FE (English and non-English European Yellow) | Map script pointer manipulation (arbitrary code execution | Map script pointer item ball manipulation) | Text pointer manipulation (arbitrary code execution | Item ball manipulation | Mart buffer overflow) | Trainerless instant encounter glitch

Bad clone glitch (Generation II)

????? party overloading (Type 0xD0 move glitch | ????? map corruption | Celebi trick | Celebi Egg trick | Shiny Celebi trick | Glitch move map corruption | Overloaded party map corruption | Glitch Unown (Glitch Unown map corruption) | Duplicate key items glitch (Infinite items and item creation, Expanded Balls pocket (Wrong pocket TM/HMs, Glitch Pokédex categories))

Closed menu Select glitches (Japanese Red/Green)

Dokokashira door glitch (International) | Fossil conversion glitch (international) | Second type glitch | Skip to Level 100 glitch | Trainer mutation glitch | Walk through walls (International) | Lift glitch | Badge describer glitch

Pomeg glitch (Generation III)

Pomeg data corruption glitch ("Glitzer Popping") | Charm glitch

Voiding (Generation IV)


Broken escalator glitch (Japan only) | Elite Four door glitch (Japan only)

2x2 block encounter glitches (Generation I)

Left-facing shore tile glitch (in-game trade shore encounter trick, Old man trick, Trade link up shore encounter trick, Fight Safari Zone Pokémon trick) | Viridian Forest no encounter grass tiles glitch

Glitch City

Safari Zone exit glitch | RAM manipulation | Out of bounds Glitch City (Generation II) | Slowpoke Well out of bounds corruption (French Gold/Silver/Crystal)

Large storage box byte shift glitch

Storage box remaining HP glitch | Generation I max stat trick

Pikachu off-screen glitch

Trainer corruption glitch

SRAM glitches

Generation I save corruption | 255 Pokémon glitch | Expanded party encounter table manipulation (Generation I) | Send party Pokémon to a new game (Generation I) | Generation II save corruption | Mailbox glitches | Mystery Gift item corruption | Trainer House glitches

Trainer escape glitch

Death-warp | Ditto trick | Experience underflow glitch | Mew trick | Text box ID matching | Meta-map script activation

Walk through walls

Ledge method | Museum guy method | Rival's effect | Select glitch method (International Select glitch method), Brock Through Walls

Surf down glitch

Grass/rock Surfing glitch (Spanish/Italian only) (adaptions: Submerge glitch (international)) | 8 8 (0x7C) grass/rock surfing glitch (English Red/Blue))

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PRAMA Initiative a également une page sur Pokémon cloning (Generation II).
Bulbapedia also has an article about Pokémon cloning (Generation II).

The Pokémon cloning method in Generation II was among the first methods discovered and is arguably more well-known than the methods for Generation I.


  • A Pokémon Gold, Silver, or Crystal Version cartridge.
  • An empty Box on the PC.
  • A Box that isn't full.
  • Pokémon to be cloned.
  • Another Pokémon to keep in the party.


1. Save the game.

2. Deposit the Pokémon to be duplicated into a Box on the PC.

3. Switch to an empty box on the PC.

4. You will be prompted to save the game for changing the box. Choose "YES" to the prompts, but shut off the power three seconds after the game starts to say "SAVING...DO NOT TURN OFF THE POWER.".


When the game is turned back on, there should be the Pokémon deposited into the PC in your party, and it should also be in the Box where it was deposited.

Another possibility is that there will be two of the Pokémon in the Box. [clarification needed]


  • Up to 5 Pokémon can be duplicated at a time under normal circumstances.
  • Items can be duplicated this way by making the cloned Pokémon hold the item to be cloned.
  • This can possibly damage the PC, and cause Pokémon to disappear. Details on this and why this can happen is not known.


Saving the game for changing the box is handled a little differently than saving the game normally. It consists of three steps:[1]

  1. The contents of the active box (before changing) is saved to the SRAM.
  2. The number of the active box changes, and the contents of the new box is loaded from the SRAM.
  3. The game is saved as normal.

If the game is reset after step 1 has finished but before step 3 starts, then the contents of the active box is updated, but the party (a part of the main game data) is not, resulting in Pokémon cloning.

Although the save file is protected by a 16-bit checksum and a backup copy, they only apply to the main game data, so this glitch is not prevented. Furthermore, this means that even if step 3 has started, as long as the game hasn't finished writing the main save file, the main save file would likely be detected as corrupt and the backup would be used instead, resulting in successful cloning anyway.

Overall, when using the change box method, the timing window to get a good clone is rather lenient:

  • On Crystal, the window is about 9–10 frames, beginning just a moment after the "SAVING... DON'T TURN OFF THE POWER." text is fully printed.
  • On Gold/Silver, the printing of the entire "SAVING... DON'T TURN OFF THE POWER." text, as well as a 16-frame delay afterwards, happens within the timing window, in addition to the aforementioned 9–10 frames.

Resetting a moment earlier than the beginning of this timing window may end up interrupting step 1 and result in the bad clone glitch, which is much harder to intentionally execute due to a smaller timing window.


  1. The function to save the game for changing the box on Gold/Silver and on Crystal. Note that the behavior of SavingDontTurnOffThePower is different on the two versions: On Gold/Silver, the function not only prints the "Saving..." text but is also responsible for actually saving the game afterwards, but on Crystal, actually saving the game happens as the first thing in the SavedTheGame function instead (before the same function prints the "<PLAYER> saved the game!" text). This causes the timing windows for cloning, and especially bad cloning, to be different on those versions.