Supported Formats

iCube reads the same GameCube and Wii disc formats as the Dolphin core it's built on. GameCube games are large (typically 1–1.5 GB per disc), so picking a compressed format matters if you're importing a lot of them.

Prefer RVZ for new dumps

.rvz is Dolphin's recommended format: it compresses well (typically roughly half the size of the raw ISO for most discs), loads quickly, and can be converted back to a byte-exact ISO whenever you need one. Avoid heavily “scrubbed” NKit dumps — Dolphin's documentation recommends converting those back to a standard format first.

Disc image formats

ExtensionKindNotes
.iso / .gcmRaw disc imageAn exact, uncompressed byte-for-byte copy of a GameCube or Wii disc. Works everywhere but takes the most storage.
.gczDolphin compressedAn older Dolphin-specific compressed container. Still readable, but superseded by RVZ for new dumps.
.rvzDolphin compressed (recommended)Dolphin's modern container. Compresses well while keeping fast load times, and can be converted back to a byte-exact ISO. Typically around half the size of the raw ISO for many discs, though this varies by game.
.wiaDolphin compressed (legacy)The compressed format RVZ replaced. Still supported for older dumps, but RVZ is the current recommendation.
.wbfsWii Backup File SystemA Wii-only container originally used by USB loaders. Strips update partitions to save space; does not support GameCube discs.
.cisoCompact ISOShrinks a disc image by omitting unused/empty sectors while keeping used data uncompressed. Supported by Dolphin and many homebrew loaders.
NKit (.iso/.wia/.rvz)Scrubbed variantA further space-saving pass on top of ISO/WIA/RVZ that discards redundant data, so the result is no longer byte-identical to the original disc. Per Dolphin's own documentation, NKit images should be converted back to a standard format before use.

Channels and homebrew

ExtensionKindNotes
.wadWii ChannelAn installable Wii Channel package (not a disc game) — the format used for Wii system/virtual console channels.
.dol / .elfHomebrew executableRaw GameCube/Wii homebrew executables, run directly without a disc image.

Getting your own dumps

Use Dolphin on your Mac or PC, or a homebrew disc-dumping tool such as CleanRip on real hardware, to rip your own GameCube and Wii discs. See Importing Games for how to get the resulting files onto your device, and the Provenance wiki guide on formatting ROMs for folder conventions.