Boot a router to other image

Now we tell the router to load the image in slot0 instead of the image in the flash memory. We use the boot command to tell the router where the image is located; by default, the router loads the first image it finds in flash memory. The boot command modifies the router's running configuration; we copy the running configuration to the startup configuration, then reboot. Upon reboot, the router loads the image from the flash card in slot0:

Router#conf terminal

Router(config)#boot system flash slot0:c3640-js-mz_120-5_t1.bin

Router#copy run start

Router#reload