Recently unboxing a UCS 420 M3, I tried to boot the server and access the CIMC , however upon pressing F8 to boot into the CIMC console, it would display the CIMC briefly with some Errors about DNS and Hostnames , then show Failure to communicate with CIMC then continue the normal boot procedure. I tried getting access to the CIMC through the BIOS ( Usually with the F8 key ) however this would not work either.

In the end I had to Update the Bios and other features of the server to the latest version (6b) via steps below

Download the HUU ISO file:

1. Navigate to the following URL: http:/?/?www.cisco.com/?cisco/?software/?navigator.html.
2. In the middle column, click Servers – Unified Computing.
3. In the right-hand column, click Cisco UCS C-Series Rack-Mount Standalone Server Software.
4. Choose the name of your model of server in the right column.
5. Click Unified Computing System (UCS) Server Firmware.
6. Choose the release number.
7. Click Download Now to download the ucs-server platform-huu-version_number.iso file.
8. Verify the information on the next page, and click Proceed With Download.