A data storage device may include: a storage configured to store user data, firmware and a boot code; and a controller configured to control data exchange with the storage, and comprising an error correction code (ECC) engine configured to perform error correction during the data exchange, wherein the ECC engine stores a first parity check matrix, performs error correction on data exchanged with the storage based on the first parity check matrix during a first operation mode, and performs error correction on data exchanged with the storage based on a second parity check matrix extracted from the firmware during a second operation mode.