I had a similar issue where it would always say media not found when trying to install a volume license copy of 2012 R2 with a bootable USB stick within the Lifecycle controller.  We had Dell technical support try as well with no luck.  After fighting with the settings within Lifecycle controller for a few hours I finally discovered that you need to change the iDRAC setting virtual media from "Auto Attach" to Attach.  Don't ask me why this worked but we had 6 identical servers here and that setting fixed it for all of them.  We didn't have any iDRAC SD media installed in any of them either.
Hi. We have recently purchased Dell Poweredge R730xd servers. I am unable to find "Boot from USB" option in BIOS. Also i am unable to deploy OS using the virtual console due to the lack of enterprise license of iDRAC8. I havn't tried installing from external DVD drive yet. What are my available options for deploying OS on Poweredge R730xd servers?
Available options for deploying OS