New WII and homebrew

What happens if I install Bootmii in a new WII 4.2U, this overwrites something that can eventually brick my wii?
I've seen a lot of sites that give you hints of installing custom IOS in order to run some hombrew applications, but what happens inside the wii, what new things are writed or overwritten in the system memory?
Thanks for any informatio you can give me.

BootMii/IOS doesn't overwrite anything, it installs to an unused IOS slot. Its unlikely Nintendo will every use that IOS slot, and if they do, it'll just be to block BootMii, nothing useful, so it is perfectly safe to install.

And if its a new Wii, you won't be able to install BootMii/boot2.

I heard that there are 256 slots.
about bootmii, yes when using the homebrew installer the bootmii line has a comment that says that it can't be installed as boot2 and the only option is to install it as IOS.
I don't have all these clear, but boot2 is the posibility to have a secondary boot IOS or something like that?
And what implies to install bootmii as IOS?

Thanks a lot, I'm new with WII but I'll learn fast.

There are 255 IOS slots actually afaik.

But anyway, boot2 is a stage in the Wii's boot process, it isn't an IOS. Its the third thing run when you press power (boot0 > boot1 > boot2 > System Menu). And installing BootMii there means you have BootMii at the earliest point possible, so theoretically, you should always be able to access it, no matter what else is messed up. For example, if System Menu won't boot, BootMii can still be accessed.

But with IOS installation, this doesn't happen. It just installs in a new IOS slot and can be loaded via HBC. It has no use as brick protection, only useful for loading homebrew apps written for MINI e.g. SNEEK and MIKE Linux Kernel.

Thanks for you very clear explanation. Now I have a clear picture of the situation.
Thanks again,
Alejandro

I almost forgot to ask.
What happens when you install some IOS that are usefull to run certain applications like GX USB Loader? (i'd like to backup mi original games and store them).
I'm not sure but I guess that after a future update, it's very likely that IOS I could have store in the WII will be erased and everything returns to "original" state? or there's a chance that my wii could be renedered useless (bricked)?

Thanks again for your help,
Alejandro

Talking about USB loaders isnt permitted on these forums, and yes a future system menu update could overwrite IOSs, and block homebrew, and in a worse case scenario possibly brick your Wii.

Ok, sorry about mention Usb Loader, but I mention it as an example.
Thanks a lot for your help,
Alejandro