Connect-X4 Lx PXE does not appear in Dell PowerEdge UEFI boot options

I have a Dell R7525 server with a Connect-X4 Lx (MCX4131A-BCAT) PCIe card. We run the server in UEFI mode, and we PXE-boot it, but I don’t see the card as an option for PXE boot.

Before posting, I made sure that firmwares etc. were up-to-date. We upgraded the R7525 to BIOS 2.1.6. We also upgraded the card to FlexBoot Family Firmware version and EFI Firmware version 14.23.17.

I also found that, although the EXP_ROM_PXE_ENABLE was on, EXP_ROM_UEFI_x86_ENABLE was disabled, so I fixed that; now both settings are on.

At this point, I can see the card in the Dell’s list of configurable devices (along with the storage controller, the daughtercard NICs, etc. But I still don’t see that the card as an option for PXE boot (I only see the daughtercard ports).

Hello Karl,

Thank you for posting your question on the Mellanox Community.

Please try setting UEFI_HII_EN to true on the adapter. This setting can be found in mlxconfig so the command would be:

mlxconfig -d s UEFI_HII_EN=1

More information on mlxconfig can be found here:

After this try rebooting the node to see if the adapter is an available as an option for PXE boot.

Thank you,


Hi Abigail, good evening,

I just checked, and UEFI_HII_EN is already set to True(1).

~ Karl

P.S. I just realized it might help to give the full configuration. So, here is the output of mlxconfig -d … query:

Hello Karl,

Thank you for the response.

To further troubleshoot this issue we will open a support ticket to work on this issue as you have a valid support contract. We will close this case and we will update the support ticket once we have opened it.

Thanks and regards,

~Mellanox Technical Support