Main part of firmware is stored on the platters in so-called Service Area. https://luxuryever704.weebly.com/blog/wdc-wd3200aaks-00l9a0-driver-for-mac. If one of the modules gets corrupted the hard drive fails to initialize correctly and stops working making the data inaccessible. Firmware of the drive is not located on the logic board as most people think. Service Area occupies the negative cyli..