Faraway Island Mew being flagged as illegal after it uses "Transform"

[ranqt]

So I found this topic

And I tried to play with the savegame with VisualBoyAdvance, the character was already in the Faraway Island, I just needed to catch Mew. I tried several attempts in order to find the correct nature and so on, and I discovered that PkHeX flags illegal the Mew after he uses "Transform".

I attach you the relative battery saves from VisualBoyAdvance, one captured after the Transform move (flagged as illegal), and another captured after 2 tries while he was still in its form.

I don't know if this should be fixed, but I just wanted to show this.

Please let me know your opinion about this. I think it comes by mimic the IV of my pokemon? and thus, making it illegal. But I did't use any cheat code, so basically if I own a Japanese copy of Emerald, and I caught a Mew there after a transform, will my Mew will become illegal, even if it's legit 100%??

(At leat, illegal according to PKHeX)

ILLEGAL-TRANSFORM.SAV

LEGAL-NOTRANSFORM.SAV

[ranqt]

I want to add that I didn't try anything particular, I was just chasing mew in the wild, not looking for particular frames and such stuff, I just wanted to catch a regular mew in that place, didn't matter about the shiny-ness or IVs, I was just reseting hoping to fing a good nature.

[theSLAYER]

@ranqt there's no such thing.

Given that you're using an emulator to catch Mew: emulators sometimes have hiccups during PIDIV generation, which can cause legality issues.
[such hiccups are problematic, because actual hardware generation won't lead to those]
Your Mew is illegal due to IVs. (How the RNG works, is that PID is called first, then the IVs)

I've just tested it with a single state save, and both Mew, transformed or not transformed, PID and IVs are exactly the same.

If you don't believe me, try bumping into the Mew, then press A (to trigger encounter), and immediately state save.
Then capture on state where it transformed, and capture another state where it didn't transform.
You're gonna need to save the game after both states, and export both saves. Then compare the Mew on both saves.
 

[ranqt]

Okay, thanks a lot for the clarification!

Illtry to buy from eBay a real JAP cartrdige and do it there to be sure it will be legal 100%

[theSLAYER]

1 minute ago, ranqt said:

Okay, thanks a lot for the clarification!

Illtry to buy from eBay a real JAP cartrdige and do it there to be sure it will be legal 100%

or you could keep doing that on emulator, but dispose the ones that have illegal PIDIVs. I imagine finding a affordable real JAP cart right now isn't the easiest thing to do..

[ranqt]

Yep the price is quite high, but I think it worths its value. It should be around $40, I just need to find the cheapest vendors
They usually sell Nintendo stuff at reasonable prices, so there might be a chance ill find a JAP Emerald that isn't too expensive!

[theSLAYER]

Just now, ranqt said:

Yep the price is quite high, but I think it worths its value. It should be around $40, I just need to find the cheapest vendors
They usually sell Nintendo stuff at reasonable prices, so there might be a chance ill find a JAP Emerald that isn't too expensive!

beware that some of the cheaper units might be faked (or they seem to commonly call it reproductions right now), and those aren't official, and chances are you won't be able to back up the save properly. Keep a lookout, read all the details thoroughly :3

[ranqt]

Yep dont worry I have some trusted vendors on my fav list, not those general chinese vendors that have 40 copies available, but the ones that occasionally put random used Nintendo and/or games for sale. I kinda snipe them, and yes Im very carefully with the repro cartridge, sounds arrogant but I bought many games and I constantly google for confirmation, and I still have to find something that really makes me think "is this repro or not?", they ALL have some flaw somewhere that can be easily spot, specially once opened! Ty again