Symptom

5508 controller may reboot without an output in the crash file.

Conditions

Console : fpga: Lost heartbeat from Environment controller, system will reboot in 5 seconds!!! Syslog server if configured : %ENVMON-0-KEEPALIVE: wlcng_powerSupply.c:280 System is rebooting in 5 seconds: lost heartbeat from environmental controller

Workaround

Downgrade to 6.0.220.0. More information: Although the release notes on CCO may state otherwise, this bug is not fixed, and will not be fixed, in 7.0.230.0, 7.2.130.0, or any runtime image. It is fixed only by applying a special FUS image, which updates the FPGA, Environmental Controller, and USB firmware in the controller. To find out whether your WLC needs to have the FUS image applied, issue the command "show sysinfo". A WLC with the fixed firmware will show "FPGA 1.7" (or above.) The fixed FUS image is now available on CCO (version 1.7.0.0-FUS.)

Further Problem Description