This post is a warning. Only to make people aware of a “VERY VERY BAD PRACTICE”. I have managed to kill my lab Cisco WLC 4402 yesterday. We all know that routers and switches (even Standalone APs) can be upgraded through the recovery mode (it’s when the boot process is being interrupted). Some devices, like access points, support TFTP recovery, others can only be updated via XMODEM. Cisco WLC 4400 is different, completely different. If you interrupt the boot process by pressing ESC, it will provide you with the recovery menu, where one of the options is “Manually update images”. This is what I tried yesterday, unluckily.

This mode is a TRUE recovery mode. It is meant for Cisco TAC engineers, ONLY. Don’t ever try to update your WLC using this mode. Don’t ever try to format your flash via this mode (one of the available options). I have killed my device and now need to deal with Cisco TAC for recovery procedure – to recover WLC using this mode I have to provide separate images for RTOS, Bootloader, Code and probably others. Assuming this is my lab device, it is not under support anymore… the only hope is that I work for a large Enterprise, that is a large Cisco’s client. So hopefully TAC engineers can help with this personal request.

You were warned!

Update 1: I found the way to recover it. I can provide some information later. Anyone interested?

Update 2: Here’s my recovery method.