I recently had to update the BIOS and iDRAC firmware on a Dell server running ESXi. I did not have the Dell Server Updates DVDs or the time required to download them, and instead used the Dell OMSA CentOS LiveCD and the Update Package for Red Hat Linux files option. While the steps below are Dell specific, they could be modified very easily to work with just about any hardware vendor.
01. Download the Dell OMSA CentOS LiveCD, and make sure to read the README file.
02. Download the required updates from the Dell support site. Be sure to choose the "Update Package for Red Hat Linux" .BIN format for the downloads. Again, make sure to read any notes or installation instructions included with the downloads. For this set of Dell updates, the iDRAC firmware had to be updated prior to the BIOS.
03. Use ISO Master (or equivalent) to inject the .BIN files to the root of the Dell OMSA CentOS LiveCD ISO image, and then burn the image to disc. The updates could also be copied to a USB drive and then mounted from within the LiveCD.
04. After evacuating all VMs from the ESXi host and putting it in maintenance mode, boot the ESXi host to the Dell OMSA CentOS LiveCD.
05. Choose the "Boot (run from CD)" option at the menu.
06. Wait for the GUI to start, and then issue the following commands from the terminal window:
cd /mnt/live ./<NAME-OF-UPDATE.BIN>
07. When the update is complete, issue a reboot command from the GUI of the LiveCD or type the following command in the terminal window:
08. After the LiveCD completes shut down, remove it from the ESXi host. Verify that the updated firmware versions are correct, and then test your ESXi host to ensure everything is working as expected.
Thanks for reading!