I don’t think WDC did this on purpose The update situation on problematic HDDs was compounded by the fact that the Let’s Encrypt certificate expiration which effectively made the MCH unusable without a firmware update - the intersection of the two events resulted in more than a few bricked MCHs. Look into the debug_logs.zip from both MCH units and you will likely see that one had many more SMARTCTL errors than the other and that the one with a large count of SMART errors will likely not be firmware updateable - perhaps that is the reason for OTA update failure where the update program will refuse to update a HDD exceeding a threshold of errors. These hard disk errors are prevalent in SMR HDD drives and they occur frequently in HDD that are more than 50% full and written to frequently by database programs such as PLEX and the Android OS that runs MCH.
Replacing the HDD with a SSD as described in another thread will likely make the MCH system more stable and usable and last longer as I expect the MCHs that I have replaced with SSDs which have 5 year disk warranties will do. You may also be able to do a sector clone of the ‘defective’ HDD from your MCH with a same or larger drive, and be able to recover a functional MCH because such a MCH should now be able to receive OTA firmware update.
