Core Issue
The router boots to the first image in Flash when the boot system command is missing from the configuration, or when the incorrect syntax is used with the command.
Resolution
Display all available Cisco IOS images on the router. For the onboard Flash, issue the show flash: command, as shown in this example:
CISCO7507#show flash:
-#- ED --type-- --crc--- -seek-- nlen -length- -----date/time------ name
1 .. image 6FA1BD58 BE19B8 20 12327224 Jan 07 2000 02:07:35 rsp-jsv-mz.121-6.bin
4056648 bytes available (12327352 bytes used)
For PCMCIA cards use slot commands.
CISCO7507#show slot0:
-#- ED --type-- --crc--- -seek-- nlen -length- -----date/time------ name
1 .. image 6FA1BD58 BE19B8 20 12327224 Jan 07 2000 02:07:35 rsp-jsv-mz.121-6.bin
4056648 bytes available (12327352 bytes used)
From global configuration mode, issue the boot system command. Be careful to specify the correct Flash device. The filename must be exactly the same as in the output of the show flash command, and it is case sensitive.
It is very important to use the exact syntax specified with this command. Refer to the boot system command for platform specific syntax if you are not sure.
The use of invalid syntaxes may cause the router to not boot to the desired image, even though the commands are accepted when configuring the router, as shown:
boot system flash:c3640-i-mz.122-10.bin
boot system flash c3640-i-mz.122-10.bin
boot system slot0:c3640-i-mz.122-10.bin
If a boot system command that is not working properly exists in the configuration, remove it by issuing the no <current boot sytem command> global configuration command. For example, to remove the boot system slot0:c3640-i-mz.122-10.bin command, issue the no boot system slot0:c3640-i-mz.122-10.bin global configuration command. Then configure the correct syntax.
Verify that the correct command is in place by issuing the show running-config command.
These are examples of correct Flash device entries:
- CISCO3640(config)#boot system flash:c3640-j-mz.112-4.XA
- CISCO7507(config)#boot system slot0:rsp-jsv-mz.121-6.bin
