Well, if you reverted the changed you did (I assume you followed the guide on xda), then verified you have your keys and wimax_mtd is fine, I would say a hard reset couldn't hurt. Do it through recovery (wipe data), and you will most definitely not lose root. You wouldn't either through hboot, but I'm not positive it's wiping all the same stuff. It probably is, but... As for 4g, there are a few other things you might be able to try. Start with the hard reset, and see what it does. Of course, make a backup first.