The homebrew channel (HBC) is used to load homebrew apps from an SD card or USB device. The HBC is one of the main results of softmodding - and it is how you can "USB load".
Try looking at the links in my signature, there is a "a basic introduction to wii hacking" link that explains the concept of many things relating to softmodding.
May i ask, is there a particular reason you dont want to softmod?
I am not sure why your wii wants to update - but i can suggest something that should work. In my signature, there is a "Softmod ANY Wii" link. You should follow the guide from start to finish as it will downgrade your system menu to 4.1 and mess around with the settings so that your wii will not recognize that it is on an old version. If you need more info on this, let me know - i dont want to go overboard in case you dont want to softmod and this is just a waste of time lol.
So read the "basic introduction" link in my sig, decide on whether you want to just softmod over your hardmod, and let me know