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## Generation II Glitch Discussion

### Odd corruption glitch in Pokémon Crystal - Page 1

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#### Odd corruption glitch in Pokémon Crystal

Posted by: Torchickens
Date: 2014-06-11 14:42:59
I was researching glitch mail in Pokémon Crystal and I found that the mail memory addresses are the same. I also found that invalid glitch mail types are not the same between Gold/Silver and Crystal.
This is the glitchy Flower Mail type (seen for probably all glitch mail types except FF) as it appears in Gold/Silver and Crystal:
The left picture is on Gold/Silver, and the right picture is on Crystal:
[img]http://i.minus.com/jxh863lME4NBb.png[/img][img]http://i.minus.com/jbuDj4v321zOHS.png[/img]
In Gold/Silver, the FF mail type displays a non-freezing purple screen, but in Pokémon Crystal it resets the game, not causing a glitch dimension for me.
To my surprise there were weird effects when I re-loaded the save.
Firstly, my character was out of place, but warps and events still work. The out of place thing can be fixed by using Fly. Opening the menu causes the player character to disappear until it is closed again.
[img]http://i.minus.com/jcsJ1vzQlN0ds.png[/img][img]http://i.minus.com/jJhYahQ9o8Shv.png[/img]
Secondly, trying to to do a various things freezes the game or causes a Glitch Dimension.
*Use an item. (not with all items)
*Toss an item.
*Give an item to a Pokémon (sometimes).
*Withdraw an item from the PC.
*Deposit an item in the PC.
*Phone someone.
Thirdly, and possibly the glitch with the most potential, if any practical use is this:
Opening the items pack puts you into the TM/HM pocket with the cursor position (not the actual item) at #8 (hex:07). If you keep scrolling down the item description will go blank.
[img]http://i.minus.com/jfeEGTzmmHzPD.png[/img][img]http://i.minus.com/jZReLnsePeFwT.png[/img]
I don't know if it actually goes past cancel or something else happens. You can't switch the positions of items in the TM/HM pocket, so there is no memory corruption through swapping post 20 items this way if you do in fact scroll past position 20. (Apparently this glitch allows you to do something like that though?)
If you're lucky you may be able to give a Pokémon an item, but the game may reset/freeze:
[img]http://i.minus.com/jC4Gydossrfn0.png[/img]
I've only been able to give them HM08, which was the last item in the list.
I used a Pokémon Crystal save file from the internet for this, which is why my character name is 'AMANDA'.
Edit: If you take the HM08, save and reset it will be in your items pack in the items pocket rather than the TM/HM pocket.
[img]http://i.minus.com/jb1sbUbYNXngxQ.png[/img]
Edit 2: I remember when I experimented with TM/HMs in the items pocket before they had a different effect. If the item isn't always HM08 (which only has a give/toss/sel option), maybe we could activate glitch effects?
Edit 3: If you try to sell blank description items you can get tons of money with no freeze. Yay. This does cause memory corruption though. I will see if any glitch Unown give you FF type mail next.

#### Re: Odd corruption glitch in Pokémon Crystal

Posted by: pokechu22
Date: 2014-06-11 15:11:59
Partial resets? I actually remember something like this. Now I will need to search thru some spreadsheets, and I know it was gameshark based, but I think I remember something else that caused an effect like this. Though it was slightly different.
EDIT: Found it! Pokémon Edición Amarilla (Spanish Yellow Version), set $D611 to 0x35. Then, enter the Viridian City PokéMart (only tested without already having done the oak's parcel stuff; start a new game). The game does some stuff, but it isn't very interesting, unlike this one.
EDIT2: Video.

#### Re: Odd corruption glitch in Pokémon Crystal

Posted by: Torchickens
Date: 2014-06-11 16:23:37
Ooh, that's pretty interesting. Shame that after trying that the game freezes for me on the title screen (but not the intro).
No luck in finding a suitable Unown so far. Strangely all but one I tried didn't corrupt the mail box (the odd one out was 2B that made a repeating 00 39 corruption). I don't know if me originally having no mail in the box had anything to do with it.
Interestingly, when I tried Glitch Unown hex:22 with the code 0122D9DE the game reset itself and then skipped the intro and loaded the "Clear all save data?" No/Yes screen. From there no buttons would do anything. Strange.

#### Re: Odd corruption glitch in Pokémon Crystal

Posted by: pokechu22
Date: 2014-06-11 16:27:39

> Ooh, that's pretty interesting. Shame that after trying that the game freezes for me on the title screen (but not the intro).

Same thing happens to me, which is unfortunate. I didn't remember the entire details when I made the original post. Also, here is a video of this effect.
EDIT: I can't get the effect from this main post to work in crystal. I've tried it in both VBA-M and No$GMB. The latter is giving an unknown opcode warning. Which emulator do you use?

#### Re: Odd corruption glitch in Pokémon Crystal

Posted by: Torchickens
Date: 2014-06-12 08:48:31
I used this emulator.
New find. When this glitch happens, a lot of values in memory addresses from CFBB-E080 become 07. E081-E0A4 also become 07, but these are reset to other values.
One of the notable addresses is D22D, the battle type modifier, so you can turn wild Pokémon into Trainers. Trainers themselves mess up too, all I tested have a Squirtle (07) that knows Fire Punch x4, with abnormally high Special Attack.
Edit: A video is worth 1000 words.
I switched to VBA-RR v23.6 svn480 because it doesn't have certain graphical bugs. In that emulator, the effects happened but without the use item freezes, but to know for sure what's the correct behavior someone needs to try this on a real Game Boy.
Edit 2: I checked all glitch Unown and found no Unown you can use to get an FF type mail, though I did find various map corrupting Unown: 3A, 80, 8B, 8D, 90, 9E, A1, C0, D3. But it's a shame I couldn't get to the Fuchsia City train door with them.
Edit 3: Kylemsguy tried it on a real cartridge. https://www.youtube.com/watch?v=27xAM7w42TI
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