An optical disc drive includes a firmware memory, a buffer memory, and a system control chip. The system control chip includes a processor and a memory update controller. When the optical disc drive is under a normal mode, the memory update controller is in an idle state. The processor controls the optical disc drive to fetch an update firmware from an optical disc and store the update firmware into the buffer memory. When the optical disc drive is under a firmware update mode, the processor is in an idle state. The memory update controller fetches the update firmware from the buffer memory and stores the update firmware into the firmware memory without the processor executing an update routine code.