A Firmware Over-The-Air (FOTA) based data update method and a mobile terminal of supporting the same are provided. The FOTA based data update method for a mobile terminal includes loading a pre-boot file stored in a second memory in a pre-boot loading area of a first memory, identifying version information of a first version bootloader file stored in a first bootloader file area and a second version bootloader file stored in a second bootloader file area, loading a newer version bootloader file, corresponding to a new one of the first version bootloader file and the second version bootloader file, in a bootloader loading area of the first memory, loading, upon bootloader file activation, a FOTA engine and activating the FOTA engine, and updating, upon FOTA engine activation, a bootloader file area storing the older version bootloader file on the basis of received boot related data.