Uploaded July 2014 | Updated September 2026, 3 weeks ago
When Surf is used in the limit between two maps so that the player starts surfing (its sprite changes to lapras) in the tile that marks the beggining of the new map, the new map will not be loaded, and the [block data of the] current map will be loaded again instead. The connection data of the map remains, including the blocks that correspond to the strip of the connected maps, as these blocks were loaded when the old map was loaded (in this case, an area of 3x9 blocks from the left Route 27 and same from the right of Route 29).
Eventually, or possibly earlier due to the alignment of the connected maps, the X and Y coordinates will reach certain values that will make the game freeze (in this case, the Y coordinate will underflow at one point). But if you go back to the corrdinates of the original maps before, everything will be back to normal.
In reality this bug is never found obviously, so all things considered it can't be called a bug. The tile in the right of New Bark Town was hacked if you haven't noticed; it was originally a water tile (w/ ledge).
When Surf is used in the limit between two maps so that the player starts surfing (its sprite changes to lapras) in the tile that marks the beggining of the new map, the new map will not be loaded, and the [block data of the] current map will be loaded again instead. The connection data of the map remains, including the blocks that correspond to the strip of the connected maps, as these blocks were loaded when the old map was loaded (in this case, an area of 3x9 blocks from the left Route 27 and same from the right of Route 29).
Eventually, or possibly earlier due to the alignment of the connected maps, the X and Y coordinates will reach certain values that will make the game freeze (in this case, the Y coordinate will underflow at one point). But if you go back to the corrdinates of the original maps before, everything will be back to normal.
In reality this bug is never found obviously, so all things considered it can't be called a bug. The tile in the right of New Bark Town was hacked if you haven't noticed; it was originally a water tile (w/ ledge).


![Pokemon Gold/Silver - Create your own custom trainer with coin case
From Bulbapedia: If the player has used Mystery Gift, he [Cal] is replaced with a Trainer with the same name and party of the last person the player used Mystery Gift with.
Coin case glitch: http://forums.glitchcity.info/index.php/topic,6716.0.html
Coin case setup as a memory editor: https://www.youtube.com/watch?v=ffZjCabeNr4
How to spell each hexadecimal number with the box name: http://pastebin.com/4ZDpQXGe (remember that the first four characters of the box name are the 2-byte address, and the last two characters are the byte to write on that address).
In order to be able to write to the SRAM (where the game stores the data of the variable trainer of the Trainer House), we need to enable it first and to open bank 0 in particular. Because of this, we need to add a few more lines to our code spelled out with items. Heres the full list: http://pastebin.com/vjBywmiL
Everything else is explained in the video. Pokemon Gold/Silver - Create your own custom trainer with coin case](https://i.ytimg.com/vi/Y9r9Gy3Shi8/mqdefault.jpg)







![Pokemon G/S - How to get any Pokemon (coin case arbitrary code execution)
This video is outdated and reproducing it is no longer advised. Watching this video instead is recommended: https://www.youtube.com/watch?v=PsIb3OZaYAs
It is a detailed tutorial of a far more versatile Coin Case arbitrary code execution approach that can be used for multiple purposes, and includes examples and troubleshooting.
Help wont be offered in the comments section of this video, other than to redirect to the video linked above. This is because 90% of your ambitions or troubles with the Coin Case glitch are covered or can be avoided by following the steps explained in that other video. This is, in fact, the reason why Ive made that video.
Old video description below
Coin Case glitch: http://forums.glitchcity.info/index.php/topic,6716.0.html
This trick is based on the Bug Catching Contest feature in Gold and Silver. By setting the contest status flag, we can trick the game into believing that the player is currently participating in the contest. The address of the species of the Pokemon caught in the contest can be edited during the trick so that the player receives whichever Pokemon he wants.
The species is read from the fifth party Pokemons current HP stat (the lowest byte). A Pokemons current HP is probably the easiest RAM address to manipulate even though its not exactly easy.
Heres the suggested ASM/Hex code and corresponding item list for this trick: http://pastebin.com/fCRime06. Note that the Quagsire must be holding Protein (as well as Sleep Talk as the first move). None of the required items is especially difficult to obtain, though you may need to start a new game if you have lost access to some of the TMs required. Note as well that the trick assumes the player beaten the rockets in Mahogany, as the contest status flag shares its RAM address with the rocket event flag, and the value being written into that address during the trick clears the latter.
The obtained Pokemon will retain the data of the Pokemon you last caught in the bug catching contest, including known moves (not future learned moves), DVs, stats and the like. If you level up your Pokemon or deposit it in the daycare, their stats will get back to normal. Note that if the growth rate doesnt match its possible that the Pokemon grows a rare number of levels after gaining experience in battle. If you had never participated in the contest before, all the data will be 0s (like myself in the video). You cant send this Pokemon into battle but you can still deposit it in the daycare to get a level 1 Pokemon back.
I you happen to have the coin case as a memory editor (https://www.youtube.com/watch?v=ffZjCabeNr4) setup working, you can use it for this trick as well. Otherwise the item list specifically suggested for this version is easier to make. Anyway, if you go with the memory editor setup, it requires two iterations for each Pokemon in the following order (note that in this case, the species byte is not read from the fifth Pokemon HP, so its not needed):
(Address) Byte:
(DCE7) Hexadecimal species identifier of wanted Pokemon
(D572) 04
No matter the method you use, you can perform the trick as many times as you want. While setting up the party and items can be more time consuming than doing the famous Celebi (egg) glitch to obtain any Pokemon, the advantage of doing it via coin case ACE this way is that after youve set everything up the first time you can repeat it as many times as you want in just a few minutes to obtain another Pokemon.
REQUIREMENTS
- A Quagsire holding Protein with Sleep Talk as the first move. Put it the fourth position of your party.
- An untrained, low level Pokemon. Put it the third position of your party. The Pidgeys or Rattatas in Route 29 are some of the best ones. Make sure that the Pokemons Special stat is not 8 and that its HP stat is not 16. Make sure the Pokemon is female as well to further increase the chances of succeding. A Pokemon that meets these three requirements will work around two thirds of the times. If it didnt work (the game froze, the level of the first party Pokemon did not change), catch another Pokemon and try again.
- In the fifth position, a Pokemon with an HP stat matching the species id of the Pokemon you want to get. For example, 151 HP if you want a Mew. This is not necessary if you use the coin case as a memory editor method.
- List of items in the PC: http://pastebin.com/fCRime06
STEPS:
- Arrange the Pokemon in your party and the items in your PC as explained before.
- Enter Prof. Elms Lab or Cherrygrove Mart.
- Leave the building and move exactly four steps to the right
- Open the Pokedex and open Machops page (so that you hear its cry). Bellsprout, Machoke and Omanyte should work too.
- Exit the Pokedex and open the bag.
- Switch the pockets in the bag at least once. Then use the Coin Case.
- [Specific for this trick] Exit the items menu and the start menu and wait for the beep. Selecting the QUIT option also works. Pokemon G/S - How to get any Pokemon (coin case arbitrary code execution)](https://i.ytimg.com/vi/a0ZZ3rIL0vA/mqdefault.jpg)