But SEUS can upgrade Your firmware to the latest version. You don't have to use SEtool 2 lite to do this. But if You would like to change your firmware from R1NA005 to R1CA021 (or any other firmware) You can use SEtool 2 lite.

Anyway, SEtool 2 lite won't unlock Your phone. To do this You will need a cruiser cable (not standard DCU-60) and a SEMC Tool , for example: SEMC Tool 8.4 Free.