The four step process to locate and load the IOS

The four step process to locate and load the IOS is as follows. First, boot from ROM and POST then check configuration register value to determine if booting into ROM monitor mode or booting from IOS. Next check for IOS boot system commands in the startup-config file and if there are boot system commands, run them in the order they are listed. Next, if boot fails, use fallback sequence of Flash, TFTP, ROM to locate and load the IOS. Then locate startup-config file and load it by copying the startup-config file to the running-config, but if no startup-config file is found, prompt for setup-mode and if that is bypassed, create a basic “skeleton” default running-config.