Type 0xD0 move glitch
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)
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
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
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
Death-warp | Ditto trick | Experience underflow glitch | Mew trick | Text box ID matching | Meta-map script activation
Ledge method | Museum guy method | Rival's effect | Select glitch method (International Select glitch method), Brock Through Walls
Grass/rock Surfing glitch (Spanish/Italian only) (adaptions: Submerge glitch (international)) | 8 8 (0x7C) grass/rock surfing glitch (English Red/Blue))
Type 0xD0 move glitch, also known as Move 0x00 arbitrary code execution (not to be confused with - (Generation I move) arbitrary code execution in Pokémon Red and Blue) is a glitch in at least English Pokémon Gold and Silver that allows the player to perform arbitrary code execution without using the Coin Case.
An advantage to this glitch over Coin Case glitch is that it may not corrupt the stack (similar to wrong pocket TM ACE which never corrupts the stack), however it requires move 0x00 which can only be obtained by trading a Pokémon with it over from Generation I (such as "-" move Ditto with the swapping Transform moves glitch), obtaining a bad clone, or using another form of arbitrary code execution.
This glitch has been used in any% speedruns of Pokémon Gold and Silver (see here), and was researched by luckytyphlosion. ChickasaurusGL also adapted it for non-speedrunning uses.
Summary
You can execute arbitrary code by moving in a specific way in Cherrygrove City (see pictures below) and viewing move 0x00 from the move description menu in a Pokémon's summary provided the following requirements are met:
- You have exactly four Pokémon.
- The first Pokémon has move 0x00 (e.g. a "CoolTrainer" Ditto).
- The third Pokémon is a low level 'slide' Pokémon you caught in the wild (whether it will work is up to chance but if you find one that works it will always work, possibly the same one compatible for Coin Case ACE without bad DVs etc.)
- To be safe have Pokémon 2 and 3 have the bird and tailed creature menu sprites and have no Pokémon hold an item except for Pokémon 4.
- Pokémon 4 is a Quagsire with TM02 and Return as its first move (for box name ACE at D8C0 (box 1 character 2)) or a Quagsire with HP Up and Sleep Talk as its first move (for stored items ACE at D61A (second item quantity)).
Before you move one step up and four steps right from picture 3, save the game. Afterwards view Pokémon 1's moves from the move description menu and close it repeatedly until your code works.
Example box name code
This box name code, conceptualized by Crystal_ and optimized by TimoVM, allows us to warp to the Bug-Catching Contest and obtain Celebi.
The box names for that are as follows:
Box 1: p 0 5 é ! 6 ? z Box 2: H é 'm 2 p 'v 6 5 Box 3: é A 't h 'd
Technical information
When viewing the party screen or the move screen, the game displays small Pokémon icons and animates them based on their current hit point values and status. While it is doing this, the game stores the animation data in a structure starting from address $C51C, which lies right beyond the end of screen tile data at $C508. The game can store and animate up to 10 sprites this way. In particular, the move screen only has a single animated sprite (the current Pokémon's icon in the top left of the screen).
An important field of the animation data structure is the animation type, stored in address $C51E (wSpriteAnim1AnimSeqID) for the first animated sprite. This is used to index a jump table that is used to control the behavior of the animation. By overwriting this address with an invalid value, we can index this table out of bounds, potentially triggering ACE.
The glitch type 0xD0 (the type of move 0x00) can overwrite $C51E by overflowing the tile data when its name is printed on the move screen, if said name is long enough. The source of the type name is 0x8350 in VRAM, hence affected by what is or was displayed on the screen; in particular, the party screen may affect 0x8350 if you have enough Pokémon menu sprites and/or held items in the party[citation needed]. This also means that the name is susceptible to VRAM accessibility: if the game attempts to read a character while VRAM is inaccessible it will read value $FF and print a '9' instead of the expected character. This means that the effects of the glitch can differ depending on the exact timing of the name being printed on screen.
Overall, it might be difficult to manipulate the data written to $C51E exactly. However, due to the structure of the code located right after the jump table, a reasonable amount of pointers will land in the vicinity of either the $C9xx region or the $E9xx region (echo RAM for the $C9xx region). For smaller maps, execution will safely slide until it reaches three regions:
- $CC20 contains wBGMapBuffer, which temporarily buffers newly inserted tile IDs.
- $CC48 contains wBGMapPalBuffer, which temporarily buffers newly inserted tile palettes.
- $CC70 contains wBGMapBufferPointers, which temporarily buffers VRAM addresses of newly inserted tiles.
All three of these are affected by the movement pattern of the player. wBGMapBuffer and wBGMapPalBuffer do not contain much useful data, but can fairly easily be manipulated to allow execution to safely slide through, while wBGMapBufferPointers can be directly manipulated to jump to a small selection of possible addresses.
Due to the specific movement pattern used, wBGMapBufferPointers starts with the byte sequence of DA 9B FA (jp c, FA9B, at $EC70), which causes the game to execute $FA9B (echo RAM for $DA9B).
As $DA9B is Pokémon 3's Speed DVs, we can make the data slide over to Pokémon 4. Using Quagsire, the code can be redirected to somewhere else (such as box names or stored items) where we can spell out code.
The consistency of the glitch can be increased by having a specific player name consisting of a single kind of character (eg. "RRRRRRR"). When the game encounters a 0x52 control code character, it will print the player's name, filling a 7-byte range with the same value and increasing the odds of writing the desired value to $C51E.
The effect pointers are sourced from DoSpriteAnimFrame.Jumptable ($23:5473 in EN G/S). This ROM bank contains several minor version differences, leading to some version-exclusive effect pointers.
Here is the assembly code for the box name code to obtain Celebi:
AF xor a ; a = $00 F6 FB or $FB ; a = $FB, Celebi species ID EA E7 FC ld [wContestMon],a E6 B9 and $B9 ; a = $B9 50 ld d,b 87 add a, a ; a = $72 EA D2 F8 ld [F8D2],a AF xor a ; a = $00 D6 FC sub $FC ; a = $04 FB ei 50 ld d,b EA 72 D5 ld [wStatusFlags2],a ; located at $D8D2, $72 written by earlier code A7 and a, a ; reset carry flag D0 ret nc
YouTube video
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