Reinstall grub2

mount /dev/md2 /mnt
mount /dev/md1 /mnt/boot
mount -t dev -o bind /dev /mnt/dev
mount -t proc -o bind /proc /mnt/proc
mount -t sys -o bind /sys /mnt/sys
chroot /mnt

grub2-install /dev/sda

dd bs=512 count=1 if=/dev/sda 2>/dev/null | strings|grep GRUB

egrep ^menuentry /etc/grub2.cfg | cut -f 2 -d \'

grub2-set-default 1

grub2-editenv list