Upgrading a 7030 cabinet can take 20+ minutes to complete.

To recover the slave cabinet you'll need to remove the epm board so it does back to a main cabinet for the recovery then set the correct master/slave ip's turn both cabinets off, reconnect the epm board then power both cabinets back on.

I hate 2 cabinet 7030's. After bricking a couple using.the update slave I just stopped using it and just used the above procedure.