Try using LoadMii as your homebrew launcher from the Indiana Pwns exploit. That should be able to run RiiVolution.

If you had a cios installed before, it should be fairly simple to install a HBC with a different title id to stop it getting deleted. Do a search for "HBC JODA.wad", if you can install that with wad manager (using ios250) then you will solve a tonne of problems. There is a way around this if you didn't have a cIOS installed before you upgraded but I won't go into that here. I might type up a guide for hacking a virgin 4.3 soon.