If wiikey 2 is one of the good chips, then you can do any update you want
as long as it is from the correct region.
There are some chip that can't handle the latest kind of 001 error or BCA protection(New Super Mario Bros), and then those games won't work from disc channel with the latest official update installed.
Oh and if you have trucha signed discs(patched in
any kind), they will stop working. Your NSMB for example could be one of them, as many people need to patch it to play it.
Pete666 said:
The only problem you'll probably have is that your wii won't be region free after the update..
Mine was okay, but after, can't play PAL games! (I'm Ntsc)
It was never as region free as a loader anyways and i hope you know that. And when using a loader, Gecko OS, Gecko OS mod or SoftChip to name a few suited for modchip users, your Wii will be region free (again).