you are already unlocked your bootloader..so you don't need get identifier token again to unlock your bootloader..
1. first way..like what rzr86 and jmcclue said above..because you're still s-on but already had unlocked bootloader..they've suggest you to installing 4ext recovery for the next future you can easily installing of custom rom...because 4ext recovery is already option "SmartFlash" that fuction can installing custom rom with automatically supported also installing a boot.img from the rom itself under s-on devices like yours..
to installing that 4ext recovery...you can download recovery.zip from
here.., then extracted that recovery.zip file to get recovery.img file...then copied recovery.img file to your sdk / adb folder (that are a same place as your adb.exe and fastboot.exe), after that...you can boot your phone to bootloader mode..then select "FASTBOOT" from there, then plug your phone to pc..until indicator in the phone has "FASTBOOT-USB", after that you can open cmd from your adb folder (just press and hold shift + right click on empty space from that folder and select "Open command window here") ...then typing command "
fastboot devices" ..see if the output has detect your phone serial number.. if so...then continued typing "
fastboot flash recovery recovery.img" then "
fastboot reboot-bootloader" done..now you can tested it go to your 4ext recovery..and now you can enabled it "SmartFlash" from tools option before you installing any custom rom from 4ext recovery...
2. second way...if you don't want change you cwm recovery..you can fix your booting stuck by just flashing a boot.img extracted from the rom.zip itself with manual flashing from fastboot..
to do that...firstly just copied rom.zip that you wanna installing to another folder..then extracting / unzipping that file...then copied boot.img to your adb / sdk (same place as your adb.exe and fastboot.exe) folder..then after you've already installing that custom rom from cwm..you must reboot your phone to bootloader again (don't booting the rom first), then select FASTBOOT from there..then plug your phone to pc until indicator in your phone has FASTBOOT-USB..then open cmd from your adb / sdk folder..then typing command "
fastboot flash boot boot.img" then "
fastboot reboot" done...now you can see that the phone can booting of the rom normally or not..
hope this help..