Kaphotics

Actually yes; block 4 is the tail end of the game progress block. You can try zeroing that block out and re-exporting with PKHeX.

Blocks A-D are stuck with an old revision (18) while the rest of the save blocks are at 29-31 Other than that, we can do the same rebuilding/rearranging of blocks to create a new save file (attached). Pokemon - FireRed Version (USA, Europe) (Rev 1).sav

Block 4 is the first box & half of box 2. Every other block is present, so everything about game progress is there. I uploaded a fixed save for you

Block 4 was missing from both main & backup, so that section of box data is gone. Other than that, we can do the same rebuilding/rearranging of blocks to create a new save file. POKEMON_EMER_BPEE00.sav

The script you linked is old and does not handle the fixed gender requirements of the starter Espeon and Umbreon (both of which must be male, and never shiny). Since Eevee is 87.5% male, statistically it'll be "right" more often than not, but it will produce inaccurate results frequently. It works for Eevee, simply because Eevee is not locked to a single gender (and can be shiny). "locks" are a community term for requirements/disallowed features. In this scenario, a "gender lock" is when a Pokémon is only to be generated with a specific gender, and the game generating loop is locked in a repeating loop until it meets the criteria. When an NPC's team is generated, it usually has non-shadow Pokémon before the capturable shadow Pokémon. These non-shadow Pokémon have their own requirements, that cause the RNG to loop until satisfied, being nature and gender locks. In XD, the developers also disallowed shinies from being generated for the NPC (and the player), hence a "shiny lock".

Pretty sure you set the PID to 0 or 1 and the game will interpret that as random / random-noshiny.

Adapt the script to search whatever criteria you want. Keep in mind there are only 2^16 seeds, so you need to consider if it is statistically possible. 5 flawless IVs is 1:2^25, which means a spread probably won't exist.

You have to progress through the story. Wasn't a hard google search...

If the program has an editor, then it should have a randomization tab. If not, then it hasn't been researched/implemented, or isn't advisable.

Read the second line of the message. You need to dump the base ROM in addition to the latest game patches. pkNX only works with the latest files.

PKHeX is "complete" for validating a given PID/IV being obtainable or not, and considers shininess as well. Only XD prevents shinies for shadow encounters.

Load a Gen3 save file.

Save file editors cannot change the ROM, use a ROM editor instead.

Check next to the executable for any error log file. Also try deleting the config file from a previous release.

SW/SH might have special "permissions" for uploads not matching the original data not being rejected outright, but you'll still get mismatches on HOME's server data. There is no game mechanic to change balls, so once HOME has seen it once, you should NOT be changing any immutable values as it can be detected as someone using cheats. https://projectpokemon.org/home/forums/topic/56296-read-home-tracker-value/

You cannot legally change balls after HOME has seen the data. There will always be a mismatch with the data stored in HOME. How to get around it? You don't. You start with an untransferred Pokémon with the correct ball, and be satisfied with that.

Event gifts in generation 4 have a hard-coded version they are received with.

Check the verbose report. Ability capsule exists.

Write your own linqpad script that creates the file name as you want it; positional properties are not stored in PKM data and are irrelevant when loading. The PKM database will load from save files and can be used to see box/slot within the save file it resides.

Property copy syntax requires an asterisk before the property name you wish to copy from.

Encounter slot checks were implemented. You can't just select any PID/IV, as it must show up via Method K for the encounter slot it has, along with special restrictions for IVs unique to the bug catching contest.

Don't adjust the TID/SID -- the game generates the starter immediately after generating the save file's TID/SID, thus they're correlated, like the message says. If you are not using the trainer database feature, it likely is pulling your currently-loaded save file as the trainer data source, so just temporarily change your save file's TID/SID prior to generating from the encounter.

Not sure why you're looking at code from a version of PKHeX from 7 years ago. The latest PKHeX release will generate an Eevee matching the trainer's TID/SID.