RusticoNES Core for NES on iPhone & iPad | Retropa

Catalog systems and formats

RusticoNES builds on an upstream project at https://github.com/zeta0134/rustico. What Retropa documents is narrower than that project at large, and wider than one console: your NES / Famicom files appear in the catalog as .nes, .fds, .unf, .unif. Seeing an extension on that list is a starting point, not a verdict on any single game. Bring your own dumps; the app ships no games and no BIOS files.

• NES / Famicom: .nes, .fds, .unf, .unif

Cartridges, UNIF and disk images

A NES / Famicom cartridge image and a Famicom Disk System image are different inputs. UNIF is a cartridge container format, not another name for an iNES header. Preserve the original header and extension when importing; renaming or removing bytes to make the file look like another format can discard information used to identify its board.

• Keep a separate copy of the original image.
• Read any disk-system BIOS prompt; Retropa does not provide the BIOS.
• NSF audio formats are not listed for RusticoNES; check TetaNES instead.

First launch and controller checks

Get the image onto the device first: a cloud placeholder looks identical to a real file in a list, but the import fails until the bytes are actually local. Import it through the Retropa library, then confirm the app detected NES. Leave the default skin on and skip display effects for now. Press the directional pad, A, B, Start and Select, diagonals and simultaneous presses included. If one input goes missing in your own layout, suspect the layout before you suspect the mapper.

When a cartridge fails but others work

Mapper hardware differs from cartridge to cartridge, and RusticoNES implements some boards rather than all of them. A recognized extension does not prove the board used by a particular game is implemented. Write down the exact error, plus the mapper and region if your dump metadata names them. Random header patches rarely help, and no BIOS cures a board that was never emulated. With disk games, work out first whether the BIOS or the disk data is the missing piece.

Core switching and keeping progress

Retropa Plus unlocks core switching. That applies to NES as well, even though NES plays for free. Before comparing RusticoNES with TetaNES or JGenesis, confirm that the other core lists your file's format at all. Retropa remembers your pick per game. Copy out both the game's own save and the save states made under the old core, then bring up the same moment in both cores and judge sound, picture and input.

• RusticoNES save states stay tied to its mapper and core state; do not treat them as cross-core files.
• Copy and verify the NES save before changing cores; RusticoNES will not migrate it on your behalf.
• A RusticoNES comparison does not repair the image or supply firmware that is absent.

Compare only the overlapping formats

Formats are collected per system page, so the NES page can show a longer list than any single core supports. RusticoNES has the shorter list of the NES cores: .unf and .unif are its own, while TetaNES covers NSF and NSFE. Check the target core's catalog entry against the file you hold before spending a Plus switch on a comparison. Same scene, same default display settings: a new skin or filter muddies which core actually changed something.