Choice of filesystem has nothing to do with raid. You can put any FAT32 partition, including the ESP, on a raid1 if you want. You just need to make sure to use md format 0.9 or 1.0 instead of 1.1 or 1.2 so the firmware will still recognize it.
** Changed in: grub2 (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1466150 Title: Feature request: For EFI system grub-install should be able to install to multiple disks To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1466150/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs