An NKIT file is a disk image of data extracted from NintendoWii and GameCube games. NKIT is for Nintendo Toolkit format. The resultant compression ISO file utilizes the main data of these games to be run with emulator programs such as Dolphin, Swiss, and Nintendont. NKit comes in raw (iso) adn compressed (gcz) file formats which were both designed keeping in view playability and size.
NKIT File Format
NKit file format is a non-lossy format and is used for shrinking and restoring Nintendo Wii and GameCube images. The formats are available in ISO and GCZ file formats for each of GameCube and Wii games.
Same as compacted GameCube iso
GCZ is Dolphin’s own block seekable compression format
RVT-H format only playable in Dolphin
RVT-H in GCZ playable in Dolphin only
The NKIT file format header is as follow.
NKit Header ‘NKIT’
NKit Version ’ v01'
Source image original CRC32
NKit CRC - makes the NKit file CRC32 equal the source CRC at 0x208 (at 0x4 in GCZ)
Source image length
Forced Junk ID (When Disc ID differs - rare - GameCube only)
Wii Update partition CRC32 if removed when converting