[quote name='Rig']Either way, I updated all my...channels...before updating to 4.2. Zero issues for me, as everything still works.[/QUOTE]
Official statement from Nintendo, posted on Oct 6th:
"Nintendo of America's consumer service department has received less than 200 inquiries regarding system menu update (SMU) 4.2 since it launched on September 28, 2009.
This is from a U.S. installed base of over 21,000,000 Wii consoles. A significant number of these inquiries were resolved quickly and easily right over the phone. For the remaining inquiries we have advised consumers that the symptoms described usually occur when a Wii console has been modified."
http://www.n-sider.com/contentview.php?contentid=3953
In this case, modified doesn't mean "have homebrew channel installed" - it means consoles from the wrong region being flashed and sold, or consoles that have actual modifications made.
Is the whole issue completely overblown? Some people in this thread seem to think it's a serious problem. I still haven't seen any evidence of that, or even heard from someone with a legit Wii that was bricked because of the update.
Yes, it's possible... but it's highly unlikely that anything bad will happen when you update the console as long as you don't interupt the power while updating.