This works fine on an NTSC 4.1u wii. I installed IOS 56 5662 with WAD manager 1.4. It then let me access the shop channel without having to update, and I downloaded the latest NetFlix channel. Since I used the shop channel, NetFlix didn't have any updates. After installing. I was still a little paranoid since it took the shopping channel a while to load, so I made sure all of my homebrew stuff worked, and it did.
I normally just boot to the system menu since I have channel forwarders for everything I use. However I guess the next thing I would like to do is make it so I can load NetFlix from inside the homebrew channel. It looks like there's a BootNetflix (based on BootOpera) I can use to do this. I will install this sometime soon. If I recall it's on the homebrew browser.