Booting issues with Jelly Bean are widespread. I let AdAway reboot my phone after downloading ad blocking hosts and it would never again go beyond the Google splash logo. Nandroid wouldn't restore, full wipe and reflash JB ROM wouldn't boot, full wipe and flash ICS ROM wouldn't boot. Had to Odin and lose all data on the device. Fortunately I backed up my SD partition contents prior to this fiasco after reading similar horror stories. Done with it until customs are source built.
Tapped via Galaxy Nexus LTE..