Recently, I've seen a lot of shiny editing guides that are out of date ill be covering odds editing (Gen 1-5)
Lets start out with Gen 1 (Technically Remakes)
Editing Fire Red odds are as simple as downloading ShinyCC. This file editor only works on English Copies of the Rom. From what it says it works on the following games.
Fire Red
Emerald
Ruby
Next Gen 2. (Remakes)
Now if you wanted to edit the odds of you getting a shiny in the original gen 2 games. All you would need is PKHex and do some breeding. (Shinies are determined by IVS in that game. Create a Shiny Ditto with Max IVS then breed)
But In the Remakes were gonna have to do some code editing.
Open CrystalTile2
Open the Rom in CrystalTile2
Then Click on the DS
Then Select the Arm9 File and then Extract it.
Open the Arm9 with a Hex Editor. (HXD)
Ctrl + G and go to offset of 0x70080
Change the 08 Value to FF
Save then add it back to the Rom
Your odds with roughly be 1/256 (256/65536)
Gen 3
Emerald and Ruby have already been covered in the first post within Gen 1
I would just recommend playing Emerald if you have it!
Gen 4
I'm gonna assume you're using Platinum. Both Diamond and Pearl don't have as much Pokemon to find.
You DO NOT need to decompress this file to edit the odds.
Open your Platinum Rom in HXD
Ctrl + G
0x79E50
Edit the Number 08 to FF
1/256 Chances (256/65536)
Gen 5 (Black and White)
Open CrystalTile2 and Decompress your file (More Detailed in Gen 2)
Open the Arm9 File with a Hex Editor (HXD)
Ctrl+G
0x13F0C
Edit 08 to FF
Save then add it back to the Rom.
REMAKES
Open CrystalTile2 and Decompress the File
Open the Arm9 File with Hex Editor (HXD)
Ctrl + G
0x18DF0
Edit the 08 to FF
Save then add back to the Rom
Thanks for Reading if you have anyone questions or think the guide needs to include this leave a comment and maybe I'll answer your question. I'm not the smartest when It comes to Hex Editing. If their are any errors please let me know!