Drivekey X4 confirmed working with 4.0u
I've updated to 4.0u on my wii and my Drivekey still functions as it should. So anyone worried about the new update, don't be unless you also have Homebrew installed, then don't update until the issues are totally sorted on that end of things but a plain vanilla wii using drivekey is fine to update.
v4 update working for me too
Thanks to previous poster. Just thought I'd increase the sample size by one. My drivekey is also functioning properly after updating to v4.0. This also helped me to get a few recent games working (e.g., madworld).