Well, if you move the flashbackup.tar.gz from one controller to another, the procedure should be:
(1) Make sure the new controller is the same platform as the old (3000 series to 3000 series, etc). Make sure it is also the same version of code as the old if possible.
(2) copy the flashbackup.tar.gz fileoff the first controller and to the new controller
(3) restore the backup to the new controller and paste in the new controller's licenses before you reboot (DO NOT type "write mem")
(4) Reboot the Controller, once again, without typing write mem
(5) The New controller should be just like the old.
Each step is crucial.