1140 and 1250 series APs do not require the use of the Cisco Upgrade Utility.
By far the easiest way to upgrade is:
- Plug the AP into an 802.11af POE switchport on a subnet with an active DHCP scope.
- Telnet into the AP by IP address once it comes up.
- Login using telnet. The default vty/password combo is: Cisco/Cisco. The enable password is also Cisco.
- Issue the following command in enable mode:
archive download-sw /overwrite /reload tftp://10.241.0.128/c1140-rcvk9w8-tar.124-21a.JA2.tar
The whole process is very quick. The AP will download the image, overwrite the standalone IOS image in nvram and reboot in less than a minute.
You can watch the whole process through a simultaneous console connection, of course.