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Generation I Glitch Discussion

'Pokémon Brown Mode' (Pokémon Yellow) - Page 1

'Pokémon Brown Mode' (Pokémon Yellow)

Posted by: Torchickens
Date: 2018-01-16 15:27:33
This is a 'glitch' in Yellow I may have discovered that allows you to start a Glitch Dimension with brown colours, possibly derived from unused Trainer 0xFF ("TM55")'s AI. Currently it is Game Genie only, but may be possible with ws m with the help of modified Trainer battle routine.

It also doesn't seem to be RAM dependent (other than possibly from what Game Boy mode you're using) as I tested it on two save files and set breakpoints for RAM, but I don't know for sure.

On Pokémon Yellow, enter the following Game Genie codes:

3E0-2E9-B31
FF0-2F9-C49

As well as GameShark code 01C958D0 (rosters loaded from other trainers and/or non-roster 00s may not work the same).

Try to fight the glitch Trainer that appears and the battle will restart with you in a cave. Do this six more times and the game may suddenly reset.

[img]https://i.imgur.com/6j0MSpd.png[/img] [img]https://i.imgur.com/wY24HTU.png[/img]

It's an amazing coincidence this exists, but I guess with so many things that can happen in the game something like this would eventually happen.

Note: You may have to be on Game Boy Color mode for this to work. This didn't seem to do the reset on Super Game Boy mode (nor Game Boy mode, though I don't know if effects would be visible if it did) for some reason.

Re: 'Pokémon Brown Mode' (Pokémon Yellow)

Posted by: Flandre Scarlet
Date: 2018-01-16 16:12:23
Something similar happened to me once. After using 8F to activate walk through walls I walked out of bounds on accident. Somehow the game ended up resetting rather than crashing and everything was blue (I was in the indigo plateau if that could have affected it). I unfortunately didn't record it and this occurred quite a while ago. So this glitch or at least a variation of it is possible on console but I'm convinced it was luck that it ever happened in the first place.

Re: 'Pokémon Brown Mode' (Pokémon Yellow)

Posted by: Torchickens
Date: 2018-01-16 16:37:50

Something similar happened to me once. After using 8F to activate walk through walls I walked out of bounds on accident. Somehow the game ended up resetting rather than crashing and everything was blue (I was in the indigo plateau if that could have affected it). I unfortunately didn't record it and this occurred quite a while ago. So this glitch or at least a variation of it is possible on console but I'm convinced it was luck that it ever happened in the first place.


Interesting. Good to know. Thanks for this Flandre Scarlet. :)

Yeah, other colours are possible. With cheats once I got "Pokémon White", which isn't very useful but still interesting.
https://www.youtube.com/watch?v=IqqUgEvPM_Y

I have found out how to encounter TM55 (Trainer FF) with ws m.

ld b,3d
ld hl,(another address in RAM goes here)
call 3e84

@hl address (unbanked RAM?):
ld a,ff
call 6030
ret

I tried using the bank switch function (3e84) as it is meant to be used intentionally (load ROM address hl at bank b) but the value for the 'a' register was changed during this routine. This workaround means you're still on bank 3D, but the game has a chance to call 3D:6030 with a modified a register by executing code in RAM where the bank is irrelevant.

Unfortunately I can't replicate the effect this way yet. D058 is normally 0 outside of battle, and if you change it to another value you'll just encounter a regular trainer after attempting to attack. Trying to work around this with things like forcing the map 0xFE and having code in its script to redirect back to itself (maybe still wouldn't give a Glitch Dimension however, and likely not a brown one as the cave is brown).

Re: 'Pokémon Brown Mode' (Pokémon Yellow)

Posted by: Torchickens
Date: 2018-01-16 17:22:54
Update: This is the closest I've got so far.

@DA7F:

ld b,3D
ld hl,DA87
call 3E84
ld a,2E
ld (D63F),a
ld a,FF
call 6030
ret

;After selecting a move, we warp to map 0xC6 (a Victory Road map), which uses the meta-map script represented by a byte at D63F. 0x2E is an out of bounds value that executes F3CD (D3CD).

@D3CD: jp DA7F

This causes the battle to restart immediately, like keeping the Game Genie codes on but with the glitch meta-map script instead. Sadly this resulted in a freeze after 5 battles or so.

Re: 'Pokémon Brown Mode' (Pokémon Yellow)

Posted by: Torchickens
Date: 2018-01-16 21:30:00
News! It turns out artificial trainer classes aren't so hard to access after all (at least partially). Address D031 (Red/Blue)/D030 (Yellow) controls the actual Trainer class ID in battle according to the game. Code 01FF30D0 won't change the picture and name of the trainer, nor parties but does seem to change the AI to match the relevant trainer.

Still haven't been able to replicate this effect without Game Genie (perhaps it's very specific) but now we have a way of replicating the escape battle and warp to Victory Road effect without having to run part of the battle script. This may even be possible with Super Glitch (however normally in Red/Blue and not Yellow due to screen data updating when you enter battle) without the need for arbitrary code execution.

Edit: I did it!!! :DD

You can just force 01FF30D0 on the Lorelei battle to get the brown Glitch Dimension. Now it's time to test that with OAM DMA hijacking.

Edit 2: Setting it to FF each time will also suffice, so you can use this item code with an item 3 bootstrap.

Item 3: Lemonade x255
Item 4: Carbos x208
Item 5: X Accuracy x48
Item 6: Poké Ball x119

Edit 3:

01FD30D0 on Lorelei. It's luck dependent and I don't know if it works for every save.

[img]https://i.imgur.com/DP5rQB7.png[/img]