C-Series servers use firmware downloaded from cisco.com. This firmware is certified by Cisco to upgrade firmware on a C-Series server.
The firmware you download is packaged in a .zip file. After you have downloaded a firmware .zip from Cisco, you can use it to update the firmware on your server. Cisco also provides release notes with each image, which you can obtain from the same website from which you obtained the image.
Do not use the .zip file to reimage your server.
You use a .bin file to reimage. You must extract the proper .bin upgrade file from this .zip file. You can extract this .bin to a TFTP server or your local machine. As you see in Installing CIMC Firmware Through the Browser or Installing CIMC Firmware from the TFTP Server, you can reimage using an TFTP server or a browser on your local machine.
When you update the firmware, you can either upgrade an older firmware version to a newer one, or downgrade a newer firmware version to an older one.
The CIMC separates the firmware update process into stages to ensure that you can install the firmware to a component while the server is running without affecting its uptime. Because you do not need to reboot the server until after you activate, you can perform that task overnight or during other maintenance periods. When you update firmware, the following stages occur:
During this stage, the CIMC transfers the selected firmware version to the server. The install process always overwrites the firmware in the non-active slot on the server. You can install the firmware using either of the following methods:
Through a browser client—This method allows you to browse for a firmware image on your computer and install it on the server.
From a TFTP server—This method allows you to install a firmware image residing on a TFTP server.
During this stage, the CIMC sets the non-active firmware version as active and reboots the server. When the server reboots, the non-active slot becomes the active slot, and the active slot becomes the non-active slot. The firmware in the new active slot becomes the running version.