Yellow LED Blinks Forever (Factory Reset Didn't Work)

My Cloud OS 3 Personal & Network Attached Storage My Cloud
4

Solved at least for me:

WARNING!!! DO IT UNDER YOUR RESPONSABILITY YOU ARE VOIDING WARRANTY!

http://community.wd.com/t5/WD-My-Cloud/How-to-unbrick-a-totally-d ead-WD-My-Cloud/m-p/632129#M2347