According to http://scanlines16.com/en/blog-3/retro-gaming/game-cube/gamecube-korean-master-list/,
Korean GC releases use the following country codes:
- E or W for games in English
- K for games in Korean
- Unknown value for games in Japanese (my guess is that they might
have made the discs bit-for-bit identical to Japanese releases
because the regions of these games are already set to NTSC-J)
As far as I know, the GC has no Taiwanese releases, which is what
the W country code is used for on the Wii. But I could be wrong.
A small note: The country_byte == 'K' check in the code isn't
actually necessary as long as RegionSwitchGC returns NTSC_J
for 'K', but I thought it would be better to not rely on that.
c8b4645039