These disc images are only used on dev units and not retail units.
There are two important differences compared to normal Wii disc images:
- The data starts 0x8000 bytes into each partition instead of 0x20000
- The data of a partition is stored unencrypted and contains no hashes
Our old implementation was just guesswork and doesn't work at all.
According to testing by GerbilSoft, this commit's implementation
is able to read and extract files in the filesystem correctly,
but the tested game still isn't able to boot. (It's thanks to their
info about unencrypted disc images that I was able to make this commit.)
We shouldn't try to create folder names that contain characters
such as : or / since they are forbidden or have special meanings.
(No officially released disc uses such characters, though.)
Before, if you extracted a directory like /map/Final/Release/,
Dolphin would create the nested folders map, Final and Release
in the output directory and put the files in Release instead of
just putting the files directly in the output directory.