Guides:Coin Case ACE

This is a guide on how to execute and/or exploit a glitch. For a more technical overview of the glitch involved, see Coin Case glitch.

This page serves as a repository for a Coin Case ACE setup for the English versions of Pokémon Gold & Silver. It is part of the TimoVM's gen 2 ACE setups set of guides.

Please make sure to fully read every step of the guide before executing them.

If you encounter any issues when going through this guide or would like to provide feedback, please contact TimoVM on the Glitch City Research Institute Discord.

General overview

When using the Coin Case while a Bellsprout/Machop's cry and specific newly loaded tiles are buffered in memory, the game will execute code in various places before finally ending up in the $FA98-$FA9B range, which is echo ram containing the stat exp data of party pokémon #3.

Using specific stat exp values, we can form a jump to $CF00, which is located in the latter half of last read mail. This gives us barely enough space to fix the side effects of using the Coin Case and jump to the start of box names.

In practice, the initial Coin Case ACE setup will be created using the following general process:

1. Train a pokémon by exclusively defeating a set of specific encounters within Union Cave and route 33
2. Give a mail to the trained pokémon with specific content
3. Obtain the Coin Case

Step 1: preparing a pokémon that can be used with the Coin Case

1. Either on route 32 or route 33, catch a pokémon that is (preferably) at least lvl 6 and not a Hoppip. Give it a specific nickname, such as "BOXCODES" to remember that it will be used as part of a Coin Case ACE setup that executes box name codes.
2. Have it fight the following pokémon and defeat them solo (order doesn't matter, the pokémon must be the only pokémon to gain experience from the battle)
   • Rattata - Route 32 or Route 33
   • Hoppip - Route 32 or Route 33, higher spawn rate on route 33 compared to route 32
   • Hoppip - Route 32 or Route 33, higher spawn rate on route 33 compared to route 32
3. Have it fight the following pokémon with the help of exactly one other pokémon (the experience must be shared between exactly two party pokémon)
   • Onix- Union Cave
4. The "BOXCODES" nicknamed pokémon must never gain experience from any other battle
5. Buy a Flower Mail, can be bought in Goldenrod Dept. Store
6. Finally, give the "BOXCODES" nicknamed pokémon a flower mail with the following language-specific content:

Step 2: Obtaining the Coin Case

1. Obtain the Coin Case by picking it up in the Goldenrod Underground.

Step 3: How to execute ACE using the Coin Case

Now that we have the Coin Case, we'll need to set up everything needed to actually safely use it. Using a specific setup, we can force the Coin Case to execute code starting from party pokémon #3's stat experience data. What we'd like to do is to redirect it such that box names get executed instead:

• Prepare the party to ensure that code gets safely redirected to box names.
• Prepare specific box names to run a simple test code.

Finishing the setup

Arrange your party like the following:

1. Any
2. Any
3. "BOXCODES" nicknamed Pokémon that has defeated a specific set of pokémon and is holding the previously described mail
4. Any
5. Any
6. Any

Preparing a test box name code

Rename the first box name to the following name. This box name code will be replaced later and is solely intended to verify if the setup is working correctly. Their only function is to safely exit ACE and return the game to normal:

Step 4: Using Coin Case ACE

In order to use ACE, always perform the following steps:

• Ensure the "BOXCODES" nicknamed pokémon holding the mail is in party slot #3.
• Go to any pokémon center and take the stairs up to the second floor. Save the game while you're still standing on the stairs and reset the game.
• From the stair tile, take exactly 4 steps to the right¹.
• Open the start menu, open the pokédex, then listen to the cry of Bellsprout.
• Go to the Pokémon menu and read the previously mentioned mail.
• Open the item bag, switch item pockets at least once, then use the Coin Case. This will execute ACE.

Make sure to test the setup by going through this process once. With the current box name setups, you can verify that the setup is working by checking the TM/HM pocket. The quantity of TM03 should now be 255.

If the test code still crashes, check the following:

• Did you correctly follow the previous steps?
• Is the box name code correctly entered?
• Is the content of the mail correct for the game's language?
• Did you ensure that the nicknamed pokémon only received experiences from the four specific encounters? Were both Hoppip and Rattata defeated using only the nicknamed pokémon? Was Onix defeated such that experience was shared between the nicknamed pokémon and only one other pokémon?

Anytime you wish to execute wrong pocket Coin Case ACE, you'll need to repeat the steps outlined at the beginning of this section. Always make sure the "BOXCODES" nicknamed pokémon is in party slot #2 and the held mail was read before using the Coin Case.

What to do with a Coin Case ACE setup

Now that the ACE setup has been succesfully tested, we can start expanding the setup to more easily write arbitrary data. This will be done by installing the Mail writer, a small program installed using a set of box name codes.

Use the following link to continue to the next guide: Mail writer GS

Plain text transcripts of codes

• Mail

A A A A A A A A A A A A A A A A
A A p 'v 7 ' ] . 9 'l 'l 'l p 'm z 2

• Test box name

0 9 é A ♀ h 'd [SPACE]