Evie (ChickasaurusGL) 🌺 | Using submerge glitch to encounter Mew in water-grass (no ACE challenge) (Red/Green) (ポケモン バグ) @ChickasaurusGL | Uploaded October 2021 | Updated October 2024, 15 hours ago.
(Important requirements for this glitch in the description):
Notes: This glitch is highly specific and I haven't tested it on real hardware yet, but it is possible (with arbitrary code execution, it's much easier; set D4B4 to 14; to trick the game into thinking water is grass). It's not very viable without arbitrary code execution (but maybe could be made more usable with a custom tileset pointer), but still an interesting glitch. I also decided to avoid using connection copier (assuming it works in Japanese versions?).
See also: https://glitchcity.wiki/Submerge_glitch and https://glitchcity.wiki/Grass/rock_Surfing_glitch
Without the following requirements it won't work properly; as you could get the wrong number of items, or create a Glitch City that won't let you access the water-grass, or the encounter table will be wrong, or you'll disable battles (etc.). This glitch is also dangerous, because a freezing glitch Pokémon can appear (there is a possibly it may not freeze in Japanese Blue, though).
Requirements:
1. Any Pokémon with the nickname さささささ (gives us 187 inventory items)
2. A Mew renamed at the Name Rater as just ア (must be a rename due to extraneous data). Both the nickname (so that D6B5 bit 0x7/highest bit isn't set so you don't get the spinning effect disabling encounters) and the species (as Mew will give us 21 party Pokémon; coincidentally required later, are important).
3. The Pokémon must have a very specific amount of experience; 1695813 ; for the data 19 E0 45; our tileset block pointer (this is actually the normal pointer, but the swap to corrupt the grass tile ID has the side effect of (normally) changing this). Relevant addresses; D4AA W_TILESETBANK and D4AB-D4AC W_TILESETBLOCKSPTR.
4. It must have 0 (or a multiple of 256) HP stat experience (EVs), and anything(?) between 16384-16639 Attack stat experience (EVs). You can theoretically meet these requirements with a glitch Pokémon (i.e. a glitch species or hybrid made to level over 100). In this video, I just set them manually in advance. Relevant address wMapViewVRAMPointer ; D4AD (two bytes).
5. For Mew, you must not have beaten the Jr. Trainer with a Squirtle on Route 6.
6. A Rival's effect item is nice (e.g. item 0x91)
Steps:
(Notes: Some of these may still work while slightly different, but it's good to copy this first)
0. Meet all the requirements (with 3 and 4 being the hardest).
1. Start in Route 6 and win against the Jr. Trainer (Boy Scout in Japanese) with a Squirtle.
2. Fly to Cerulean City and go to the Name Rater's house.
3. Name Mew one character (e.g. ア) (don't have it as ア in advance but make the rename).
3. Open the inventory and press Select on item 13.
4. Close with B and talk to the Name Rater again.
5. Press A on さささささ. You should have 187 items now (+glitch Cancel that isn't called Cancel).
6. Move the very specific experiences Pokémon to slot 4.
7. Without moving, open the menu and scroll all the way to the bottom, pressing B to avoid the lag name items. Make sure you're at the very bottom (this can be hard to know as the inventory has lots of hex:00 items), then press up once and press Select. The cursor is now registered as item 187.
8. Exit with B again, then swap with the Mew named ア. The music should glitch as if the game froze, but really you just have to wait until you can move the cursor on the Pokémon menu again.
9. You've now got a party of 21 Pokémon that doesn't freeze the game. Some of your party data is also corrupted, but we placed the specific experience Pokémon in slot 4 so it doesn't have that data corrupted (though its species may change, etc.) Additionally, test jumping off a ledge to see if it lets you walk through walls. If it doesn't, maybe try a swap with item 32 (the 'usual walk through walls ledge swap' and try again.
10. With walk through walls active, don't save just yet, and immediately go to Cerulean City. Walk through walls until you get to Route 24, then walk on the water.
11. Swap the very specific experiences Pokémon with party Pokémon 21. Close the menu and you should 'sink' in to the water; which the game thinks is grass now. Walk around and you may either get a freezing glitch Pokémon, Mew, Pikachu (and others I haven't verified yet..); which is the data from the Jr. Trainer you fought earlier.
(Important requirements for this glitch in the description):
Notes: This glitch is highly specific and I haven't tested it on real hardware yet, but it is possible (with arbitrary code execution, it's much easier; set D4B4 to 14; to trick the game into thinking water is grass). It's not very viable without arbitrary code execution (but maybe could be made more usable with a custom tileset pointer), but still an interesting glitch. I also decided to avoid using connection copier (assuming it works in Japanese versions?).
See also: https://glitchcity.wiki/Submerge_glitch and https://glitchcity.wiki/Grass/rock_Surfing_glitch
Without the following requirements it won't work properly; as you could get the wrong number of items, or create a Glitch City that won't let you access the water-grass, or the encounter table will be wrong, or you'll disable battles (etc.). This glitch is also dangerous, because a freezing glitch Pokémon can appear (there is a possibly it may not freeze in Japanese Blue, though).
Requirements:
1. Any Pokémon with the nickname さささささ (gives us 187 inventory items)
2. A Mew renamed at the Name Rater as just ア (must be a rename due to extraneous data). Both the nickname (so that D6B5 bit 0x7/highest bit isn't set so you don't get the spinning effect disabling encounters) and the species (as Mew will give us 21 party Pokémon; coincidentally required later, are important).
3. The Pokémon must have a very specific amount of experience; 1695813 ; for the data 19 E0 45; our tileset block pointer (this is actually the normal pointer, but the swap to corrupt the grass tile ID has the side effect of (normally) changing this). Relevant addresses; D4AA W_TILESETBANK and D4AB-D4AC W_TILESETBLOCKSPTR.
4. It must have 0 (or a multiple of 256) HP stat experience (EVs), and anything(?) between 16384-16639 Attack stat experience (EVs). You can theoretically meet these requirements with a glitch Pokémon (i.e. a glitch species or hybrid made to level over 100). In this video, I just set them manually in advance. Relevant address wMapViewVRAMPointer ; D4AD (two bytes).
5. For Mew, you must not have beaten the Jr. Trainer with a Squirtle on Route 6.
6. A Rival's effect item is nice (e.g. item 0x91)
Steps:
(Notes: Some of these may still work while slightly different, but it's good to copy this first)
0. Meet all the requirements (with 3 and 4 being the hardest).
1. Start in Route 6 and win against the Jr. Trainer (Boy Scout in Japanese) with a Squirtle.
2. Fly to Cerulean City and go to the Name Rater's house.
3. Name Mew one character (e.g. ア) (don't have it as ア in advance but make the rename).
3. Open the inventory and press Select on item 13.
4. Close with B and talk to the Name Rater again.
5. Press A on さささささ. You should have 187 items now (+glitch Cancel that isn't called Cancel).
6. Move the very specific experiences Pokémon to slot 4.
7. Without moving, open the menu and scroll all the way to the bottom, pressing B to avoid the lag name items. Make sure you're at the very bottom (this can be hard to know as the inventory has lots of hex:00 items), then press up once and press Select. The cursor is now registered as item 187.
8. Exit with B again, then swap with the Mew named ア. The music should glitch as if the game froze, but really you just have to wait until you can move the cursor on the Pokémon menu again.
9. You've now got a party of 21 Pokémon that doesn't freeze the game. Some of your party data is also corrupted, but we placed the specific experience Pokémon in slot 4 so it doesn't have that data corrupted (though its species may change, etc.) Additionally, test jumping off a ledge to see if it lets you walk through walls. If it doesn't, maybe try a swap with item 32 (the 'usual walk through walls ledge swap' and try again.
10. With walk through walls active, don't save just yet, and immediately go to Cerulean City. Walk through walls until you get to Route 24, then walk on the water.
11. Swap the very specific experiences Pokémon with party Pokémon 21. Close the menu and you should 'sink' in to the water; which the game thinks is grass now. Walk around and you may either get a freezing glitch Pokémon, Mew, Pikachu (and others I haven't verified yet..); which is the data from the Jr. Trainer you fought earlier.
