Technical Legality Questions

[pokeknight]

I've been going through some of my older saves recently, preparing them for transfer into HOME. I've managed to wrangle most of the Pokemon into states that PKHeX recognizes as legal, but there are some edge cases that I would like to examine:

1. Encounter Slot Legality

I previously edited some Pokemon without knowing about the PID/IV correlation mechanic. Most were fixable, but I couldn't find appropriate encounter slots for some spreads that could be hit with the proper H2/H4 methods. PKHeX still marks these as legal, so does that mean the HOME legality checker disregards encounter slot mismatches?

2. Egg IV RNG in FRLG vs RSE/HGSS

Guides on this site recommend setting the encounter type/met location as hatched from an egg for generated Pokemon to avoid a whole bunch of PID, IV or location mismatch issues. But isn't that only the case for Emerald or HGSS, where the RNG calls to generate PID and IV are made independently upon pickup and hatching? I assume that for FRLG there is an undocumented correlation between PID and IV even for Pokemon hatched from eggs. So is it better to avoid breeding in FRLG altogether, or if I really wanted a specific genned PID/IV combination might it be best to "trade" the egg over to Emerald to hatch? Would I have to set a Hoenn met location in that case?

Or is the reverse also true, where any breeding by FRLG-exclusive Pokemon could technically have been done in Emerald by trading over the appropriate parents, before sending the egg back to FRLG to hatch? Thus, taking advantage of Emerald's broken RNG, but with appropriate Kanto location data? Is that why PKHeX doesn't enforce strict PID/IV correlations for hatched Pokemon in FRLG?

3. Ability Slot upon Transfer

Even when a Pokemon has only one ability, its PID still distinguishes between two ability slots. But when I passage some of my Gen 3 Pokemon up to Gen 4, they all default to their first-slot ability from Gen 3. When I try to change their abilities to match their slot value, PKHeX marks them as illegal. Are all Pokemon transferred between Gen 3 and 4 set with their original ability, regardless of if they gain a new ability for their second slot upon evolution?

For example, if I transfer a Shroomish (2) with Effect Spore from Emerald to HeartGold, will it evolve into a Breloom with Effect Spore (1) or Poison Heal (2)? To make it more complicated, Numel gained Simple, while Camerupt gained Solid Rock instead. Previously all Numel had Oblivious and evolved into Camerupt with Magma Armor. If I transfer a Numel (1) with Oblivious, I expect it to evolve into a Camerupt (1) with Magma Armor. But will a Numel (2) with Oblivious evolve into a Camerupt (2) with Solid Rock, or as a transfer Pokemon with Oblivious is it restricted to Ability Slot 1 as the default slot for Oblivious, evolving into a Camerupt (1) with Magma Armor, even if its PID should correspond with Ability Slot 2? Bulbapedia says that a recalculation should occur upon evolution, but I don't know if PKHeX implements this correctly.

4. Cute Charm IV Spreads

I used Cute Charm to obtain an Adamant 6IV Scyther with PID 00000099 from the Bug Catching Contest. This is accepted as legal in PKHeX, but such a combination cannot be reproduced with PokeFinder. As there is a limited number of Cute Charm PIDs, is there a list somewhere of the best corresponding IV spreads? Or does Cute Charm completely break the PID/IV correlation, only being relevant for expanding the range of shiny Pokemon can be found for the same TID?

5. Nonstandard Method Spreads with Flawless IVs

Due to algorithmic limitations I understand that only certain natures can be associated with flawless IVs in Generations 3 and 4. However, using PokeGen I'm able to find the following PIDs that have perfect IVs, albeit via nonstandard generation methods that I've literally seen nowhere else:

Can anyone knowledgeable about the mechanics explain which types of Pokemon can be legitimately generated via these methods?

Edited August 30 by pokeknight

[Kaphotics]

1. check if the program indicates the encounter frame matching a lead, or if it just reports "X". Gen3 has vblanks which interrupt the RNG patterns, but oftentimes the lack of one will be extremely suspicious (but not provably illegal).

2. emerald saves the entire egg pid to the save file when it is generated. the other games only set 16 bits. the other random properties are generated when the egg is picked up, and technically someone could bruteforce all potential seeds to see if it was legal or not. but that isn't quick for programs to do in realtime.

3. pid%2. abilities are retained on transfer, but will change when evolved to match the ability bit (pid % 2).

4. cute charm activating just forces a range of PID values based on the gender. PKHeX calculates all possibilities while pokefinder probably doesn't handle it.

5. see #1. vblanks can interrupt, but they do not interrupt multiple times. sequential calls to the RNG are denoted A,B,C,D,E,F,G, where a vblank steals a letter and discards it. the game will resume, and won't see another vblank until 1/60th (or whatever) of a second elapses, which gives more than enough time for the pokemon to finish generating. Method 1 is just ABCD, Method 2 is AB-DE, and Method 4 is ABC-E.  A vblank happening between PID calls has been observed, but it is extremely-extremely infrequent, so it's flagged as illegal just to make those cases obvious.