Like I said I don't know bootmii as I don't use it, from what I gather its used to get out of sticky situations, and on your newer wii you can only install it as a IOS, once thats done don't do the nand back up exit out, then go to the wii menu see if HBC is there, if not you might be doing something wrong, I haven't had to use letterbomb, when I did mine I was able to use bannerbomb. One of the others that have used and know more about letter bomb and bootmii will be around, you can also go to the wiki, wiibrew.org and read up on it.