@KittyJinn Some modchips do have an option to autoboot. If the game ID starts with a '1' or '0' then it's autobootable; otherwise, it's a letter. You can modify this yourself prior to burning the game onto a disc. You don't necessarily need autoboot as it doesn't affect the way a game plays or perform.
@bowlerhat The encryption keys for the Korean Wii's are different to other regions in a way to only work with Korean-only titles, as well as to mitigate piracy. System Menu 4.2 -> 4.3 have an additional check to validate if the Korean key was tampered with, and if so, then the console will display an "Error 003" message.
AFAIK, all the autoboot option on some modchips does is patch the disc on the fly for you so you don't need to patch it (and autoboot can work with retail games too that way)
There was something called Wii Autoboot Creator but all the links are dead and I can't for the life of me find a working one.
This is the closest I got, but it asks me to sign up (which doesn't work) https://www.wii-info.fr/download-29-wii-autoboot-creator-1-0.htm