I tried to setup the “EFI System” partition at install time with software RAID1 array. I tried to avoid installing the bootloader to every disk. (I had an RAID1 with spare)
The ubuntu installer allows to set as partition type “EFI System” on the software RAID array. So I thought it would work.
After successful installation the BIOS of the Supermicro mainboard has not found any EFI-Boot partition.
So I destroyed the software RAID of the “EFI System” and installed the bootloader in chroot from a Debian-Live system. I had not to change the partition flag. It was already setup right to “EFI System”
mdadm -S /dev/mdX
mdadm --zero-superblock /dev/sda1
mdadm --zero-superblock /dev/sdb1
mdadm --zero-superblock /dev/sdc1
mount /dev/md[RootFileSystemWithBoot] /mnt
mount --bind /dev /mnt/dev
mount --bind /sys /mnt/sys
mount --bind /proc /mnt/proc
Now we remove the RAID array from config file
Edit your fstab
And last but not least install grub
mount /dev/sda1 /boot/efi
mount /dev/sdb1 /boot/efi
mount /dev/sdc1 /boot/efi
Hint: You have to use a install media or live system which is EFI Boot capable and force BIOS to boot from UEFI. (You could use my USB Stick). Otherwise EFI support in Linux is disabled.