Did you make a nand backup earlier? If so, it's probably better to just restore it.

The fact that you can still get into the system menu means that not the entire nand is corrupt (the system menu and the IOS it's loading on are still fine). It may be wise to check out the installed IOS'es and update those if needed (modmii can do that as well).


Creating a virgin nand and restoring it can be done...but it's not THAT simple to just restore any created nand on your wii. It uses keys that are unique to your wii, and you have to take into account that most wii's have some bad blocks in them. If you restore a critical part on a bad block, things won't be better. As such, it's ill-advised to use bootmii to restore any nand but the ones you created yourself.

However, onsmyswarsenegg...onswy...this program by giantpune should be able to do exactly what you're asking.

 

Among others, dop-mii and MMM can both check and update your IOS'es (just make sure not to install a stub). You can also use syscheck to verify your settings, and use modmii to download the IOS'es as wads.

Your remark on 4.3 is correct. If you have 1.0.8 of the HBC, it won't be overwritten by the update (you'll only have to reinstall your cIOS'es and priiloader...and perhaps bootmii as well). Still, I'd keep that as a backup option (after the option 'use modmii to manually update your wii').

Questions about the program are best asked in the thread itself (after reading through it and the readme, of course). I haven't tried it myself, but from the instructions, I think it uses an already made nand backup as a benchmark to find out the keys and position of the bad blocks.