Booting from a specified flash
Procedure
The following example shows use of the command to reboot the switch from secondary flash when there are no pending configuration changes in the running-config file. Typing either a [y] or [n] at the second prompt initiates the reboot operation.
Boot command with secondary flash option
switch(config)# boot system flash secondary
System will be rebooted from secondary image. Do you want to continue [y/n]?