Hello Channelss,   This knowledge base article may help you. Article Number: 000114475 SC Series: Controller Safe Mode Troubleshooting [URL] You may have to log in or create an account and log in to view the KB article.  
HelloAfter half reset a Dell Compellent SC4020,This one is now blocked in SafeMode,do you have any idea how to solve this problem?   in Serial : Storage Center (sn75015) (ttyu0) Welcome to Dell Compellent Storage Center Controller HSN 75015 came from a different Storage Center.Please remove the controller from this Storage Center andreplace with a FRU controller obtained from service depot. sn75015>    Thanks !
Dell SC4020