Emerald is not a FireRed revision. It is a different game, with a different map, a different battle engine, and a different save layout. The pret pokeemerald repository documents the US SHA-1 f3ae088181bf583e55daf962a92bb46f4f1d07b7 as the dump it builds from. That is the number I compare. A file that does not match is not the base those projects mean, even if the title screen says Emerald in another language.
The Lazarus guide names a clean Emerald image as its base. Other projects can use different games and revisions, so this page does not assign a base or patch format from a project’s name alone. Follow each release readme and compare the checksum before patching. The home tool applies either. A source mismatch means you brought FireRed, a trimmed dump, or an already patched file.
Save chips matter more in conversation about Emerald than the patch format does. People want RTC and battery behavior preserved or removed. That is the SRAM page, not an extra checkbox here. I apply the author's game patch first and only then look at a save patch if the readme shipped one.
Related pages: Lazarus, FireRed, GBA, and the Pokémon index. No ROM is hosted on this site.
