Yes, you can do it either from your settings menu or from recovery (the buttons way is the same). I would definitely do another FDR. And when you restore your apps and your settings, do it one by one... not from a backup. Redo, your app settings manually, not from a backup because the old settings from GB could be conflicting with ICS. To be on the safe side, the only thing to restore from backup should be your call log and text messages.
Don't forget to change your phone from global data to 4g/3g after you do the FDR. Go to settings --->more... (under data usage) ---> mobile networks ---> network mode ---> select LTE/CDMA .