I have done enough flashing and reading for the past 4 days. I can now provide you guys with a 100% fail-proof method for getting 4G + Root + Wifi Tether:
1. Flash it back to RUU .1
2. Do the automatic OTA update from Sprint to get you to .6 (make sure it is 1.32.651.6 otherwise do not confirm)
3. From your phone, open up internet browser and go to www.unrevoked.com and get yourself rooted
4. From your phone, go to http://code.google.com/p/android-wif...4.apk&can=2&q= and install the wifi tether application
5. Reboot the phone
6. Update the Profile by going to settings/system update/update profile
7. Reboot the phone
8. Open up your wifi tether application and enjoy!
This is a guaranteed 100% will work with 4G. If it does not work for you, please let me know and I'll do my best to help. Stay tune. I will update this thread after tinkering with toast method, flip, flip ota update, newest radio, wifi tether.