boot fix -chroot method

    mkdir /mnt/root

    mount /dev/${disk}${partition} /mnt/root # replace with disk and partition of your root device

    # if you have a separate boot device, also run this:
    mount /dev/${disk}${partition} /mnt/root/boot # replace with disk and partition of your boot device

    cd /mnt/root

    mount -o rbind /dev dev
    mount -o rbind /proc proc
    mount -o rbind /sys sys
    chroot /mnt/root

        blkid
        vim /etc/fstab
            make sure UUIDs are right (compare to blkid output)

        # replace $disk with your disk
        # this assumes you want grub on the disk, not a partition
        grub2-install /dev/$disk
        grub2-mkconfig -o /boot/grub2/grub.cfg

        vim /boot/grub/grub.cfg
            make sure UUIDs are right (compare to blkid output)

        mkinitrd

    #now you can reboot and hope it works