There are numerous “unbricking” guides one can follow. You need to know your firmware version in order to use the proper unbricking guide. In some cases you can use ANY of the unbricking IMG files to unbrick as the My Cloud will resize the hard drive upon performing a System Reset through the Dashboard post unbrick. Fox_exe’s guides have been used by more than a few here to successfully unbrick their My Cloud or when installing a new hard drive:
And all of them with broken urls!
I spent more than hour trying to find “live” threads.
Need to restore WD My Cloud from scratch after replacing broken HDD.