|  | 7.2 | Bootstrap Options in Software
| 7.2.1 | Boot system commands
The following examples show how you can enter multiple boot system commands to specify the fallback sequence for booting Cisco IOS software. The three examples show boot system entries which specify that a Cisco IOS image will load first from Flash memory, then from a network server, and finally from ROM: Flash memory -- You can load a system image from electrically erasable programmable read-only memory (EEPROM). The advantage is that information stored in Flash memory is not vulnerable to network failures that can occur when loading system images from TFTP servers. network server -- In case Flash memory becomes corrupted, you provide for a backup by specifying that a system image should be loaded from a TFTP server. ROM -- If Flash memory is corrupted and the network server fails to load the image, booting from ROM is the final bootstrap option in software. However, the system image in ROM will likely be a subset of Cisco IOS software, that lacks the protocols, features, and configurations of full Cisco IOS software. Also, if you have updated the software since you purchased the router, it may be an older version of Cisco IOS software. The command copy running-config startup-config saves the commands in NVRAM. The router will execute the boot system commands as needed in the order in which they were originally entered into configuration mode.