Think 1/8192 is too low? Want odds up ~1/257? Great! This tutorial will teach you exactly how to do that.

How to:

Step 0: Preparing

Make sure you have:

• The latest version of HexManiacAdvance (here)
• An Gen 3 English Pokemon ROM, that is not Ruby v1.2 or Sapphire v1.2 (refer to the Compatibility Table if you aren't sure) (HMA = HexManiacAdvance)

Step 1: Finding the odds

Before you do anything, make a backup of your ROM by going to File, then pressing Export Backup.

Open up HMA, choose your ROM, and in the goto search bar, search for "shiny odds". If you already have the ROM open, press the 🏠 button on the toolbar, Edit->Goto, or press Control+G.

From here, press scripts. You should see shiny.odds. If you do not see it, you may be editing an unsupported ROM (eg: German Fire Red) or a Decomp Hack, which may have shifted the shiny odd values around. You will have to find the odds manually if you are editing an unsupported ROM.

Step 2: Editing the odds

Press on shiny.odds. You should be sent a new screen that resembles the search (Control+F) screen. Double click on the top-left green number (if you haven't edited the odds, it should be 8).

Now, type in a number between 1 and 255. Then hit enter or space (you may need to tap on the number again to edit).

Press Control+S to save, and it should've all worked!

FAQ

Q: How do I know what the new odds will be?

A: The new odds will be N/65536, where N is the number you typed.

Q: How can I go above 255?

A: You can't.

Q: Why aren't ROMs from other languages supported?

A: Haven (the creator of HMA) has not implemented compatibility for these ROMs, and most likely not. Make a Pull Request if you are trying to support the ROM, and have gotten decently far.

Compatibility Table

**If your ROM is not listed here, it means it is not supported!

Game	Version	Language	Supported?
Ruby / Sapphire	v1.0 / v1.1	English	Yes!
FireRed / LeafGreen	v1.0 / v1.1	English	Yes!
Emerald	v1.0	English	Yes!
Ruby	v1.2 / v1.2	English	No.
Gen 1-2, Gen 4-8	Any	Any	No. HMA only supports Gen 3 games.
Any	Any	Japanese, French, Spanish, Italian, German	No.
Fire Red rom With CFRU	v1.0	English	No. The CFRU re-writes the shiny function. Editing the odds in HMA may bug things out.
Decomp-Edited ROM	Any	Any	No. Anything added or removed shifts things around, which may make HMA not detect the shiny odds.