: Ensure the integrity of the downloaded image by checking its MD5 or SHA-1 hash against Cisco's published values. This step verifies that the image has not been tampered with during download.

Don’t panic. You haven’t downloaded the wrong file. You’ve just encountered Cisco’s .

Do not power cycle the controller during this process. A failed FUS update can require an RMA.

It is important to clarify upfront that is a specific filename for a firmware or operating system image file used in Cisco wireless LAN controllers, particularly the Cisco 2500 Series Wireless Controller .

Always read the Release Notes for the FUS file. Cisco often hides specific hardware compatibility notes there that aren't in the main AireOS release notes.