If you want to convert an .nkit.iso back into a 1:1 "Redump" ISO for use with certain hardware or for archival, the tool needs to "fill in" the missing update data.
: Ensure the folder contains the NKitProcessingApp.exe and a Redump folder populated with Wii-specific partition data. 2. Converting .nkit.iso to .iso Download Nkit 1.4 Wii Partitions
This site is a well-known resource that hosts a pre-bundled NKit 1.4 + Wii Partitions zip file (~3.89 GB), which includes all necessary update partitions for games in their vault. If you want to convert an