Zachruff asked about how to do this on the Discord server. It reminded me an anonymous user who used the full Softmod Guide - HERE couldn't get his Korean MKW Disc to run on a modded American Wii.
It boils down to two IOS's
First thing's first is your System Menu IOS. IOS60 runs 4.1, IOS70 runs 4.2, IOS80 runs 4.3. Each disc (in its region.bin) has a region value (hexadecimal byte)
Disc Region Byte Values
0 = Japan (all Taiwan games use this disc region value)
1 = Americas
2 = PAL
3 = Unused
4 = Korea
5 = China (Chinese Wii plus Chinese MKWii never released to public)
If this region.bin byte doesn't match your System Menu region, the Wii will not allow the game to be bootable from the Disc channel.
Next is the game's IOS. This varies per game. If your Wii doesn't have a game's IOS, it can't run said game. Not only that, every Korean game runs on a different IOS when compared to its non-Korean counterpart. Mario Kart Wii runs on IOS36 which is on 99.9% of Wiis, However, Korean MKWii runs on IOS46. Considering IOS46 can only be found on real/original Korean Wiis, getting one may be a challenge.
To get around all of this (according to a person named Sayuri). Install the latest version of Priiloader. Open up Priiloader in HBC. Turn on Region-Free, uncheck 'use system menu ios', and change it to cios 249. This will bypass the region checks and force all discs to run under cIOS249.
Credits to Seeky for the Sayuri message
It boils down to two IOS's
First thing's first is your System Menu IOS. IOS60 runs 4.1, IOS70 runs 4.2, IOS80 runs 4.3. Each disc (in its region.bin) has a region value (hexadecimal byte)
Disc Region Byte Values
0 = Japan (all Taiwan games use this disc region value)
1 = Americas
2 = PAL
3 = Unused
4 = Korea
5 = China (Chinese Wii plus Chinese MKWii never released to public)
If this region.bin byte doesn't match your System Menu region, the Wii will not allow the game to be bootable from the Disc channel.
Next is the game's IOS. This varies per game. If your Wii doesn't have a game's IOS, it can't run said game. Not only that, every Korean game runs on a different IOS when compared to its non-Korean counterpart. Mario Kart Wii runs on IOS36 which is on 99.9% of Wiis, However, Korean MKWii runs on IOS46. Considering IOS46 can only be found on real/original Korean Wiis, getting one may be a challenge.
To get around all of this (according to a person named Sayuri). Install the latest version of Priiloader. Open up Priiloader in HBC. Turn on Region-Free, uncheck 'use system menu ios', and change it to cios 249. This will bypass the region checks and force all discs to run under cIOS249.
Credits to Seeky for the Sayuri message