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
Come MODIFICARE la WII mini! – Davide Galatro
How to Unhack Your Wii | Remove Your Wii's Softmod
Wii – Page 44 – Capsule Computers
Wii system update 4.3 - Pure Nintendo
New WII with firmware 4.3E; where to start? | GBAtemp.net - The Independent Video Game Community
new firmware 4.4 for wii | GBAtemp.net - The Independent Video Game Community
Just Show Me: How to update your Nintendo Wii - YouTube
Wii Menu 4.3 brings performance upgrades, removes homebrew