After performing a successful connection test on a 4.3U console, this message pops up after agreeing to perform a system update (details in comments) : r/WiiHacks
Help ) easiest way to update from 4.2u to 4.3u ? ( Offline ) : r/WiiHacks
How To Homebrew Any Nintendo Wii (Latest Version 4.3) - YouTube
How to Install Homebrew on Wii Menu 4.3 (with Pictures) - wikiHow