Allows users to select specific networks (often up to 64) for the device to operate on, which can be useful for regional compatibility.
If the unlocker freezes at 50%, the phone likely had a newer bootloader that locked NV write-protection. The only fix was downgrading the firmware via Odin3 to a 2.3.6 Gingerbread release before re-running the 1.0-v tool. sim-unlocker odin 1.0-v