Glitch City Laboratories Archives

Glitch City Laboratories closed on 1 September 2020 (announcement). This is an archived copy of a thread from Glitch City Laboratories Forums.

You can join Glitch City Research Institute to ask questions or discuss current developments.

You may also download the archive of this forum in .tar.gz, .sql.gz, or .sqlite.gz formats.

Generation I Glitch Discussion

MissingNo. Exp issues in Pokemon Yellow - Page 1

MissingNo. Exp issues in Pokemon Yellow

Posted by: AlternateLives
Date: 2014-09-06 16:34:53
Backstory: Okay, so I am using theZZAZZglitch's special Debug Yellow rom (which I'll link the video if your interested) to do something of a Nuzlock run. What I've been doing is using a D20 to pick specific hex values (1-9 = 1-9, 10-15 = A-F, 16 = 0, 17-20 = reroll) for each Pokemon I get on every route. Anyway, since there are so many indices for MissingNo., it's no surprise that I have one pretty early.

However, let's be real: MissingNo. is complete garbage, especially considering he/she/it is only viable as an HP wall for the first battle, after which it downlevels to 1. In an attempt to 'stabilize' it, I tried maxing out its experience value (by changing D178-D17A to FF FF E0, which would allow some room for gained experience rather than causing 'rollover' of the value) which I was hoping would force the Experience Underflow glitch.

It turns out, though, that MissingNo. needs a 4-byte value to grow to the next level, rather than the maximum 3-byte value, meaning that the poor guy is stuck at level 1 for all eternity. This simply won't do for any sort of a nuzlock run. So…

Question: Is it possible to edit the experience-needed value without causing significant damage to other parts of the ram, and if so, what is the ram address? I've looked in several places, and I can't seem to find it.

I guess if this isn't possible, though, this poor Pokemon is going to be sacrificial meat at some point in the near future, sadly.

Any help is appreciated!

Cheers!
AlternateLives

Re: MissingNo. Exp issues in Pokemon Yellow

Posted by: Torchickens
Date: 2014-09-06 17:27:44
Welcome to the forums!

You can make the second species byte (D16A for Pokémon 1) a Pokémon like Chansey (28) and it will start leveling up as if it was a Chansey. Only thing is that it'll use Chansey's base stats, though. You'll be able to level it past 100 though, since the max experience for Missingno. apparently allows it.

If you use the following Game Genie code, then you can give Missingno. (and only Missingno.) the growth rate of your choice:

xxF-D5A-F72

Replace xx with:

00 - Medium-Fast
03 - Medium-Slow
04 - Fast
05 - Slow

Or you could have fun with glitch growth rates xD. I don't know their formulas though, just their experiences at 100 and 255. I thought 25 would be fast at low levels, but apparently it may not be.

I imagine this code will break something. Hopefully it doesn't break something too bad.

Alternatively, you can replace regular Missingno. with fossil (B6, B7) or ghost Missingno. (B8). Those Missingno. level up like the last Pokémon in the party (other special Missingno. in the party ignored).

Re: MissingNo. Exp issues in Pokemon Yellow

Posted by: AlternateLives
Date: 2014-09-06 19:01:42
First of all, thanks for the link! That's really going to help on this run, especially if I get several glitch Pokemon.

I'll probably go the first route, since as I've said, MissingNo.'s stats aren't anything to write home about anyway. As for using Fossil or Ghost MissingNo.s, I plan to use them as a separate Pokemon from their normal cousins (nuzlocke, playing with duplicates clause: in my rules; if i've used it, the hex becomes invalid, and I must reroll. All normal MissingNo.s count as one entry, the 3 others count as another. Instant crashing Pokemon are automatically invalid.), so that's why I'm putting myself through this headache in the first place.

Thank you for the reply, and thanks for the welcome!

Re: MissingNo. Exp issues in Pokemon Yellow

Posted by: camper
Date: 2014-09-07 03:42:36
Here's a graph of Yellow Missingno.'s growth rate.

As you can see, it has decreasing (and negative) exp from level 1 to 255. It has -11.9 exp at level 1 (should be rounded down to FF FF F4, i.e. 16777204 or -12), and would not level up if it has gained exp to less than that number. Even if the amount of exp it has stays between -12 and -1, since that number is higher than what it needs to get to level 100, the amount would be set to the level 100 number (F6 39 EC, i.e. 16136684 or -640532), and it still would stay at level 1.

Re: MissingNo. Exp issues in Pokemon Yellow

Posted by: Torchickens
Date: 2014-09-07 09:54:15

First of all, thanks for the link! That's really going to help on this run, especially if I get several glitch Pokemon.

I'll probably go the first route, since as I've said, MissingNo.'s stats aren't anything to write home about anyway. As for using Fossil or Ghost MissingNo.s, I plan to use them as a separate Pokemon from their normal cousins (nuzlocke, playing with duplicates clause: in my rules; if i've used it, the hex becomes invalid, and I must reroll. All normal MissingNo.s count as one entry, the 3 others count as another. Instant crashing Pokemon are automatically invalid.), so that's why I'm putting myself through this headache in the first place.

Thank you for the reply, and thanks for the welcome!


You're welcome! If you're just encountering Pokémon, the only time glitch growth rates would come into play is for regular Missingno., 3TrainerPoké (00, not accessible with D058) and X - x, (C4). All glitch Pokémon with indices over 199 become Trainers when encountered.

However, you could change CFD7 (species) from within battle then catch the Pokémon, or use TheZZAZZGlitch's 'Give PkMn' feature and alter the level to a level for the relevant route/place. This would allow using certain Pokémon that freeze.


Here's a graph of Yellow Missingno.'s growth rate.

As you can see, it has decreasing (and negative) exp from level 1 to 255. It has -11.9 exp at level 1 (should be rounded down to FF FF F4, i.e. 16777204 or -12), and would not level up if it has gained exp to less than that number. Even if the amount of exp it has stays between -12 and -1, since that number is higher than what it needs to get to level 100, the amount would be set to the level 100 number (F6 39 EC, i.e. 16136684 or -640532), and it still would stay at level 1.


Nice, thanks for the graph. How did you make that? Did you find each experience value for every level?

At a first glance, it seems like you have to negative 'ceiling' the results each time to get the right value (e.g. in reality it has -12 experience at level 1, -142 at level 2, -420 at level 3)

Re: MissingNo. Exp issues in Pokemon Yellow

Posted by: AlternateLives
Date: 2014-09-07 15:10:33
Update: I tried messing with the species byte as mentioned in the first comment. Here's the results:

1) It worked. MissingNo. levels normally. (though the stat screen still uses the original values)
2) MissingNo. apparently takes the palette data of that species. (I used Kangaskhan, since that's an easy hex to input (02) and it's one of my favorites)
3) yes, it ignores the 100 level cap, as I accidentally discovered. I forgot that I set total experience to FF FF E0, meaning it instantly jumped from level 1 to 235, or something along those lines. Another battle did not diminish the level.

I think I'm going to keep this guy around. A 100+ level Pokemon will definitely come in handy for the final challenge of this Nuzlocke run (Agitha Ultima)!

Thanks again!