Use transfer upload datatype ap-image to back up the current lightweight AP (LAP) image in case you need to roll back.
Cause: The AP image in the new firmware is different. The WLC will push the new image to APs one by one. Solution: Pre-download the AP image before the primary update.
config ap image predownload primary
show ap image predownload status
Wait for 100% completion, then reboot the controller.
Before jumping into the technical steps, it is vital to understand why you should schedule regular updates. cisco 2500 series wireless controller firmware update
This is non-negotiable.
(Cisco Controller) > config boot primary AIR-CT2500-K9-8-5-151-0.aes
(Cisco Controller) > save config
(Cisco Controller) > reset system
After reboot, the controller will run the older image. Reapply the previous config if needed:
(Cisco Controller) > transfer upload datatype config
... (reverse of backup process)
> show boot
> show flash
You need at least 50-70 MB of free flash. If space is low, delete old unnecessary files via delete command. Use transfer upload datatype ap-image to back up
Step 1 – Transfer image to WLC flash:
(Cisco Controller) > transfer download datatype code
(Cisco Controller) > transfer download mode tftp
(Cisco Controller) > transfer download serverip 192.168.1.100
(Cisco Controller) > transfer download path ./images/
(Cisco Controller) > transfer download filename AIR-CT2500-K9-8-5-182-0.aes
(Cisco Controller) > transfer download start
Wait for “File transfer operation completed successfully.”
Step 2 – Set primary boot image:
(Cisco Controller) > config boot primary AIR-CT2500-K9-8-5-182-0.aes
Step 3 – Verify boot configuration:
(Cisco Controller) > show boot
Step 4 – Save configuration:
(Cisco Controller) > save config
Step 5 – Reboot controller:
(Cisco Controller) > reset system
Confirm the reboot. The system will reload and boot from the new image.
SSH into the controller or use the console port:
show sysinfo
Note the "Product Version" (e.g., 8.5.171.0).