Setting the default flash for bootup

To specify the default flash (primary or secondary) to boot from on the next boot, use the boot set-default flash command. The syntax is as follows:
boot set-default flash [ primary|secondary ]
switch(config)# boot set-default flash secondary
switch(config)# show flash
Image           Size(Bytes)   Date    Version
------          ----------   -------  -------------
Primary Image   : 7476770    03/15/10 K.15.01.0001
Secondary Image : 7476770    03/15/10 K.15.01.0001

Boot Rom Version: K.15.08
Default Boot    : Secondary

switch(config)# boot
This management module will now reboot from secondary
and will become the standby module! You will need to 
use the other management module's console interface.
Do you want to continue [y/n]?