Make sure you absolutely check the release notes for the software as changes to the behaviour of the wlans and settings can occur between releases.

I found it is better to ssh into the controller and upgrade it from the CLI. This gives you a running output of what is going on at each stage.

debug transfer trace enable
transfer download datatype code
transfer download mode tftp
transfer download serverip 10.1.1.10
transfer download path /
transfer download filename AIR-WLC4400-K9-6-0-196-0.aes 
transfer download start

After a successful download of the new image you should see something like:

TFTP File transfer is successful.
                                   Reboot the switch for update to complete.

Sat Jun 19 15:47:00 2010: Still waiting!  Status = 2 Sat Jun 19 15:47:03 2010: Still waiting!  
Sat Jun 19 15:47:04 2010: finished umounting

(Cisco Controller) >

Issue a ‘reset system’ and say yes to saving the config before rebooting. Remember to repeat for the bootloader file should the release notes say to do so. It takes about 2 mins for the WLC to reboot. If there are access points registered to the WLC before rebooting, they will migrate to another controller.

Check release notes of the main image re bootloader. Similar procedure, however the version on the cisco web site has a ‘BOOT’ after the name. The example below was for version 5.2.

debug transfer trace enable
transfer download datatype code
transfer download mode tftp
transfer download serverip 10.1.1.10
transfer download path /
transfer download filename AIR-WLC4400-K9-5-2-157-0-ER.aes 
transfer download start

The following output (show sysinfo) after reboot verifies the versions:

Manufacturer's Name.............................. Cisco Systems Inc.
Product Name..................................... Cisco Controller
Product Version.................................. 6.0.196.0
RTOS Version..................................... 6.0.196.0
Bootloader Version............................... 4.1.171.0
Emergency Image Version.......................... 5.2.157.0
Build Type....................................... DATA + WPS