C2691-advipservicesk9-mz.124-17.image

Since it has k9:

If you see License Level: advipservices and K9: yes, you're fine.

Networking enthusiasts rebuilding the internet of the 2000s use this image to replicate historical router setups. C2691-advipservicesk9-mz.124-17.image

conf t
boot system flash:c2691-advipservicesk9-mz.124-17.image
config-register 0x2102   # Boot normally from flash
end

Router# reload

Verify after reboot that the router loads the new image.

If router boots to rommon> mode because image is missing: Since it has k9 :

rommon 1> IP_ADDRESS=192.168.1.1
rommon 2> DEFAULT_GATEWAY=192.168.1.254
rommon 3> TFTP_SERVER=192.168.1.100
rommon 4> IMAGE_FILE=c2691-advipservicesk9-mz.124-17.image
rommon 5> tftpdnld

After recovery, set proper boot system command.

Running an old IOS version (2008 release) exposes the router to known vulnerabilities, such as: If you see License Level: advipservices and K9:

Recommendation: If used today, isolate this router behind a next-generation firewall, restrict management access (ACLs, SSH only), and disable unnecessary services (CDP, HTTP, SNMPv1/v2c).