The "S" in SNEEK indicates it runs the emulated NAND from SD, so you would have to leave the card in the whole time.
UNEEK runs from USB but still requires SD.
The "S" in SNEEK indicates it runs the emulated NAND from SD, so you would have to leave the card in the whole time.
UNEEK runs from USB but still requires SD.
There is no installation. You just copy the files to a folder on your SD or USB like a homebrew app. If you want to run your entire console in NEEK mode and you're using SNEEK then you won't be able to remove the card while it is running. NEEK (S or U) redirects all access to the real NAND to the dumped one on your storage device.
It doesn't affect the console at all. It functions like a Wii cIOS for running game backups except it doesn't install to the Wii's internal memory.