A disk drive including a disk configured to spin at a target spin speed, a servo core configured to access the disk, a first non-volatile memory configured to store a first initialization firmware, a second non-volatile memory configured to store a second initialization firmware, a first volatile memory, a second volatile memory, a non-volatile memory core configured to access the first non-volatile memory, and a main core. The main core is configured to load the second initialization firmware from the second non-volatile memory to the second volatile memory concurrently with the loading of the first initialization firmware from the first non-volatile memory to the first volatile memory by the non-volatile memory core, control the servo core to initiate spinning of the disk, and communicate with the non-volatile memory core to service host commands from the first non-volatile memory when the disk is not spinning at the target spin speed.