[CentOS] Failure to install boot loader on Dell PowerEdge R720xd

Success!

Using the gparted live DVD, I switched the BIOS to use UEFI and 
repartitioned the internal 1GB SD card to GPT, 256 MB FAT32 EFI boot 
partition, 666 MB ext4 partition for /boot, and I was off to the races. I 
was able to do a minimal install and have it boot to a login prompt. Now to 
install package groups...

BTW, all this was done using the virtual DVD drive provided by the Dell 
remote console hardware, mounting ISO files from my Win10 box. That works 
pretty nicely. No need to muck about with actual disks or USB sticks.