Can you actually connect to a wireless N network with your phone and get wireless N speeds?? Easiest way to know for sure is to set your router to wireless N only. I have a feeling the hack is not actually working on your phone, as you'd be in the minority.
After I applied the hack to my phone everything worked just fine but with wireless G only. For some reason after I rebooted it a few times, the hack actually took effect and I could connect at wireless N speeds and wifi tethering was broadcasting in wireless N, but nothing could actually connect.