All, I was able to successfully get this to work by using the following racadm command:set iDRAC.ServerBoot.FirstBootDevice PXE serveraction hardreset This makes the host PXEBoot on the next reboot and attempt to pxeboot on whatever was configured is the pxe nic in the BIOS. Noit sure why all other routes to get this working were failing but turned into a simple one liner to get what I needed accomplished. 
I have a large number PowerEdge C6420 that we have to routinely pxeboot the OS on. On previous models, we used the Legacy BIOS to PXE. This has the benefit of NOT modifying the boot order to allow us to pxeboot by rebooting the machine (redhat satellite is used to pxe, thus we can leave the boot order on PXEBoot first and it will bypass to the harddrive unless satellite is ready to pxe that machine). We could hit rebuild in satellite, then reboot the hosts and they would automatically rebuild.  After we upgraded the hardware, it appears legacy boot is not workingwith our NICs/OS/hardware combo (below is the bug we created with redhat for R640 hosts but is the same with the C6420 models): [URL]   We then migrating everything over to UEFI and were successfully able to pxeboot. This had a downside that after installing the OS via UEFI, the boot order gets automatically changed to boot the harddrive first. This causes substantial work on users to have to go into the BIOS every week and change the boot order to pxeboot the host again. We decided since we idrac on everything ,we can just use racadm to manually set this. We managed to get the appropriate racadm command to handle this on our R640 hosts by running: racadm set BIOS.biosbootsettings.UefiBootSeq NIC.PxeDevice.3-1. This works until we got to the C6420 with Mezzanine cards in them. Any attempts to list the boot device for mezzanine fails. As you can see in the attached pictures, we have the NIC set in the UEFI boot order and the server can attempt to pxe automatically. When we run racadm commands to see what the device (instead of manually setting in BIOS), it fails to find the device and the boot devices do not show up even they are set and working.At this point it appears racadm is unable to manage the boot order for our mezzanine cards. Is this a known issue or is something else going on that may be breaking us?   [IMAGE][IMAGE][IMAGE][IMAGE]   Everything being commented out is not what we expected to see. Any reasoning for this? Thanks! 
Updating UEFI Boot settings via racadm commands fail to find boot device with 
mezzanine.