First-release preparation · GBA · Mobile-friendly

One game. Simple installation.

The first public ThunderYellow release will be delivered as a complete, playable .gba game generated on your own device from your legally obtained, compatible LeafGreen ROM and our verified update patch. No separate manual IPS patching will be necessary.

Game is not yet publicly released

01 / YOUR OWN GAME

Check your LeafGreen ROM

Choose your Pokémon LeafGreen (USA), Rev 1 / 1.1 .gba from Files on iPhone or Downloads on Android. The checker verifies the 16 MiB file, GBA revision and known matching fingerprint directly in your browser.

Need the original game? Read our authentic LeafGreen cartridge and personal-backup guide. A used cartridge may not be the required revision.

Select your LeafGreen Rev 1 file

No file selected.

Your original game remains on your device.

02 / THUNDERYELLOW BUILD

Get your finished game

First Public Release — In Development. The finished game is not yet available for download.

The verified first-release patch is not yet available. When we publish it, this page will automatically enable game generation for compatible files.

View release status →

Nothing will be downloaded until a real release is verified.

No Nintendo ROM is hosted here. This installer never uploads or transmits your game file; it only reads it locally. When a game update is released, your browser will download a small patch and produce a complete ThunderYellow .gba for you to keep.

Using ROMs responsibly

ROM use & legal disclaimer: Emulators may technically load ROM files obtained from different sources, but that does not mean every download is authorized. ThunderYellow does not provide, link to, or endorse unauthorized copies of commercial games. We recommend using a lawfully obtained original Game Boy Advance cartridge and making your own personal backup where permitted by applicable law. Rules vary by location; you are responsible for ensuring you have permission to use the game file you select.

Which LeafGreen version works?

EXPECTED SOURCE

LeafGreen USA Rev 1

Game code BPGE, revision 1, 16,777,216 bytes (16 MiB). A different region or revision will not match.

SHA-1

7862c67bdecbe21d1d69ce082ce34327e1c6ed5e

This fingerprint is an exact file identity check, not a link to a ROM download.

INTENDED OUTPUT

ThunderYellow first public edition

When the project is ready, the installer will check the published patch and finished game against recorded hashes before enabling a download.

A game build will not be offered here until the verified LeafGreen-based patch is created and the first public version is approved for release.

Playing on iPhone or Android

01 / SOURCE

Keep your original safe

Store your personally obtained compatible LeafGreen file in Files. Never overwrite the original.

02 / INSTALL

Make a new .gba

After public release, select your file above and follow the installer. The newly built ROM will have a different filename.

03 / PLAY

Import into your emulator

On iPhone, open the completed .gba in Delta; on Android use Pizza Boy A Basic or another compatible GBA emulator. Start a new game and back up saves.

Where to obtain a compatible LeafGreen base

We cannot host Nintendo's LeafGreen ROM. You can locate a legitimate secondhand cartridge and back up your own copy with a suitable cartridge reader on a computer. Make sure the .gba file matches Rev 1 by using the checker above.

Find authentic LeafGreen cartridges ↗GB Operator backup guide ↗iPhone & Android setup guide →

A purchased cartridge may be a different revision or counterfeit; verify authenticity, local copying rules and the exact original SHA-1. These external links do not provide ROM downloads.

While we finish development

Get the original cover artwork

The first game release is pending, but the ThunderYellow cover art is already available.

View and download cover art →