No fix available for hardmod on 4.2 at the moment.
Nintendo designed 4.2 to remove cross region loading from modchips, something which worked really well. So NTSC disc loading is gone for you, at least if you wish to stick with modchip loading. Nintendo also built in a check into IOS70 that checks and removes the old HAXX Homebrew Channel .
So, you will need to softmod if you wish to load your NTSC games. Check the Tutorials section of the forum for Messie's Full hacking guide for 4.2 Wiis or ShadowSonic2's 4.2 softmod guide.