Default [Q] updating s3 to new lte nightlies trouble while creating backup

while getting things ready to update to the new lte nightlys, i was doing a backup. during the backup i realized my sd was almost full but to late already started my backup. well during backup my phone restarted like 2 or 3 times. it finally finished the backup. however my phone will no longer restart without going into a bootloop. i am thinking that my sd is full and hopefully that is the cause. is there a way to delete files in recovery mode. i have never had too many problems while updating. any help would greatly be appreciated. i can get the phone into recovery but i am afraid if i don't get rid of some data my phone will not start back up correctly.