Wlc 2504 7.4.100 to 7.4.110 upgrade fails

Question

Hello,
I've got a strange behaviour while upgrading my 2504 wlc from 7.4.100 to 7.4.110. I used the gui procedure to transfer the updated aes file to the wlc. The procedure started fine, finished downloading, and then the wlc got completely stuck on "Writing New RTOS to flash" message, all ap loosed connection all clients down, claimings, etc... Then after more than 10 minutes watching my laptop screen I decided to hard reboot the wlc.
Initially I saw the new image booting but, at the end, I finally figured out that the backup image instead booted and the show boot from the controller shows the following:
(Cisco Controller) >show boot
Primary Boot Image............................... 7.4.110.0 (default)
Backup Boot Image................................ 7.4.100.0 (active)
The controller now is working fine with the old image, but I need the upgrade.
What do I have to do now ? I didn't understand what happened.
Thank you for your help
bye

Answer 1

Upgrading to Controller Software Release 7.4.100.60
Guidelines and Limitations
• When H-REAP access points that are associated with a controller that has all the 7.0.x software releases that are prior to 7.0.240.0 upgrade to the 7.4.100.60 release, the access points lose their VLAN support configuration if it was enabled. The VLAN mappings revert to the default values of the VLAN of the associated interface. This issue does not occur if you upgrade from 7.0.240.0 or later 7.0.x release to the 7.4.100.60 release.
• While a client sends an HTTP request, the Controller intercepts it for redirection to login page. If the HTTP request intercepted by Controller is fragmented, the Controller drops the packet as the HTTP request does not contain enough information required for redirection.
• We recommend that you install Wireless LAN Controller Field Upgrade Software for Release 1.7.0.0-FUS, which is a special AES package that contains several system-related component upgrades. These include the bootloader, field recovery image, and FPGA/MCU firmware. Installing the FUS image requires special attention because it installs some critical firmware. The FUS image is independent of the runtime image. For more information, see http://www.cisco.com/en/US/docs/wireless/controller/release/notes/fus_rn_1_7_0_0.html.
• If you are using a Cisco 2500 Series controller and you intend to use the Application Visibility and Control (AVC) and NetFlow protocol features, you must install Wireless LAN Controller Field Upgrade Software for Release 1.8.0.0-FUS. This is not required if you are using other controller hardware models. For more information, see http://www.cisco.com/en/US/docs/wireless/controller/release/notes/fus_1_8_0_0.html.
• After you upgrade to the 7.4 release, networks that were not affected by the existing preauthentication ACLs might not work because the rules are now enforced. That is, networks with clients configured with static DNS servers might not work unless the static server is defined in the preauthentication ACL.
• On 7500 controllers if FIPS is enabled, the reduced boot options are displayed only after a bootloader upgrade.
Note  Bootloader upgrade is not required if FIPS is disabled.
• If you require a downgrade from one release to another, you might lose the configuration from your current release. The workaround is to reload the previous controller configuration files saved on the backup server or to reconfigure the controller.
• It is not possible to directly upgrade to the 7.4.100.60 release from a release that is older than 7.0.98.0.
• You can upgrade or downgrade the controller software only between certain releases. In some instances, you must first install an intermediate release prior to upgrading to software release 7.4.100.60. Table 2 shows the upgrade path that you must follow before downloading software release 7.4.100.60.
For more information :
http://www.cisco.com/en/US/docs/wireless/controller/release/notes/crn74mr1.html#wp976667