We recently had to upgrade our 5520 to 188.8.131.52 from 184.108.40.206
To speed up the process, I had pre-downloaded the new image to all APs (a mix of 3502i & 3702i). So we rebooted the controller, and after it completed the boot process, all the 3702 APs joined without issue. The 3502s did not join and instead, it looked like they were downloading the new code.
After a while, all the 3502s finished picking up the new code and joined. I am at a miss why they failed since I had pre-downloaded the code to all APs.
Has anyone ran into this before?