Pokémon Romhack Base, based off pret's pokeemerald decompilation. See the wiki for more info.
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Nephrite ede39900dd Fix Dream Eater Substitute test (Gen 5+)
The test used HP_BAR(player) to capture damage, but when a Substitute
absorbs a hit the battle engine fires a SUB_HIT event, not an HP_BAR
event. The drain logic already uses INCLUDING_SUBSTITUTES so the heal
fired correctly. Fix by switching to SUB_HIT(player, captureDamage:
&damage) and changing damage to u16 to match SubHitEventContext.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-03-21 14:28:34 +00:00
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libagbsyscall
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src Fix Embargo not blocking trainer item use in battle 2026-03-21 13:28:28 +00:00
test Fix Dream Eater Substitute test (Gen 5+) 2026-03-21 14:28:34 +00:00
tools Merge branch 'master' into master-merge 2026-03-20 22:48:44 +01:00
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About pokeemerald-expansion

Gif that shows debugging functionality that is unique to pokeemerald-expansion such as rerolling Trainer ID, Cheat Start, PC from Debug Menu, Debug PC Fill, Pokémon Sprite Visualizer, Debug Warp to Map, and Battle Debug Menu Gif that shows overworld functionality that is unique to pokeemerald-expansion such as indoor running, BW2 style map popups, overworld followers, DNA Splicers, Gen 1 style fishing, OW Item descriptions, Quick Run from Battle, Use Last Ball, Wild Double Battles, and Catch from EXP Gif that shows off a number of modern Pokémon battle mechanics happening in the pokeemerald-expansion engine: 2 vs 1 battles, modern Pokémon, items, moves, abilities, fully customizable opponents and partners, Trainer Slides, and generational gimmicks

pokeemerald-expansion is a GBA ROM hack base that equips developers with a comprehensive toolkit for creating Pokémon ROM hacks. pokeemerald-expansion is built on top of pret's pokeemerald decompilation project. It is not a playable Pokémon game on its own.

Features

pokeemerald-expansion offers hundreds of features from various core series Pokémon games, along with popular quality-of-life enhancements designed to streamline development and improve the player experience. A full list of those features can be found in FEATURES.md.

Credits

If you use pokeemerald-expansion, please credit RHH (Rom Hacking Hideout). Optionally, include the version number for clarity.

Based off RHH's pokeemerald-expansion 1.15.0 https://github.com/rh-hideout/pokeemerald-expansion/

Please consider crediting all contributors involved in the project!

Choosing pokeemerald or pokeemerald-expansion

  • pokeemerald-expansion supports multiplayer functionality with other games built on pokeemerald-expansion. It is not compatible with official Pokémon games.
  • If compatibility with official games is important, use pokeemerald. Otherwise, we recommend using pokeemerald-expansion.
  • pokeemerald-expansion incorporates regular updates from pokeemerald, including bug fixes and documentation improvements.

Getting Started

Important: Do not use GitHub's "Download Zip" option as it will not include commit history. This is necessary if you want to update or merge other feature branches.

If you're new to git and GitHub, Team Aqua's Asset Repo has a guide to forking and cloning the repository. Then you can follow one of the following guides:

📥 Installing pokeemerald-expansion

🏗️ Building pokeemerald-expansion

🚚 Migrating from pokeemerald

🚀 Updating pokeemerald-expansion

Documentation

For detailed documentation, visit the pokeemerald-expansion documentation page.

Contributions

If you are looking to report a bug, open a pull request, or request a feature, our CONTRIBUTING.md has guides for each.

Community

Our community uses the ROM Hacking Hideout (RHH) Discord server to communicate and organize. Most of our discussions take place there, and we welcome anybody to join us!