I noticed that there is an error in your logs about a leftover gpt partition table still being on the disk. Can you run sudo grub-probe -t drive -d /dev/sda1, and post the results?
** Changed in: grub-installer (Ubuntu) Status: Confirmed => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1311725 Title: Installation crashed after grub setup on md array To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub-installer/+bug/1311725/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs