I'd say you can get the latest IOS files using NUS and run them through freethebug, but DoP-IOS is updated already so you can use that to have all of them
Still on 3.2... you're retarded there's no reason NOT to be on 4.1
latest IOS files keep discs from asking for updates, but then so does one of the hacks in preloader.
so some technique found? DoP-IOS = latest IOS with Trucha
Safe? Of course! installing the latest IOS files does not mean you are installing system menu 4.2... just the new IOS.
There is even a third option (many here find it to be a stupid option, but it's still an option) and that's install cIOSCORP 3.4. It makes *almost* all IOS version numbers the maximum value so your Wii will not ask you for an update. (a disc might still ask though unless you disabled it in preloader or startpatch)