Having just fitted the WiiKey, and flashed with f/w 1.9s all seems good.
But, its asking for a update, can i still carry on and perform the updates via internet?
Im on Wii f/w 3.4E at present.
(brilliant site for Wii info!!)
It will always ask for an update if there is one available. At the moment I would hold off because there is no way to go back from 4.0 but there is from 3.4.
There are no games that require 4.0 so at the moment I would leave it as it is until you know forsure that you don't want HBC.
If you don't want homebrew then updating is ok but make sure you understand what your limitations would be so research that first.