Go to the xda page I linked for radios.
Download the cdma radio
Leave it zipped
Rename it to pg05img
Move it to the root of your sd card (not in any subfolders... directly onto the main directory of the card)
Power the phone off... power back on while holding the volume down rocker at the same time until you see the white hboot screen.
The pg05img zip will automatically start installing itself
Select yes to update when asked using the volume keys
When its done installing... select the option to reboot the phone.
Remove the cdma radio (pg05img.zip) off of the sd card.
Download the Lte radio from the xda page that's linked..
Repeat the same steps as above.
When done ...don't forget to delete the pg05img from the sd card a second time.
You can use Astro file manager (from the market) or your computer to rename and move the zip files.. which ever is easier for you.
Both radio files cdma and lte... are the last set of radios on the xda webpage under Gingerbread radios.
CDMA: 1.48.00.0906
LTE: 0.01.78.0906
You can follow the Guide for better detailed instructions on installing radios:
http://forums.androidcentral.com/th...-backup-restore-install-roms-thunderbolt.html