I apologize if this message isn't as coherent as possible, it's 5:15AM over here and I haven't had any sleep.
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Softmii is a set of applications, CIOSCorp and Preloader.
CIOSCorp allows you to play backups without the need of a booting channel, as it patches the main system files* and allows burnt games to be directly read.
Preloader is a combination of things, it's like starfall but even better in some aspects. This also patches over system files. It's a fail-safe if you wii ends up bricking, so you can boot into preloader and attempt to fix it. The same codes that starfall has and even more are in Preloader.
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Starfall is something that also patches over system files. This can also save you from bricking, but only in some specific situations. There are a few codes in starfall, but the list is no where as vast as preloaders.
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If don't mind using a backup channel, then just install starfall hacks.
If you want (almost full?) brick protection and the ability to just shove a disc in and just play, then SoftMii.