dell power edge 860 bios usb

have old server play with and learn with. Trying to setup linux firewall. i think bios is at a03 get message about microcode and cpu. SO trying to upgrade bios from USB. No matter what I try cant get to or see usb. 

I have used Rofus to put image like freedos and it won't boot. Have disable network adapters pxe. F12 only search pxe.  I have selected boot order ide is checked., cant got into usb its autoset to auto.

 any help would be greatly appreciated. I have googled alot but guessing since options are referring to function keys like f11 which is not an option must be for a newer server?