اگر ممکنه اینو بررسی کنید که کجاش مشکل داره
ubuntu@ubuntu:~$ sudo fdisk -l
WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.
Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0xa4214fd2
Device Boot Start End Blocks Id System
/dev/sda1 1 1953525167 976762583+ ee GPT
Partition 1 does not start on physical sector boundary.
Disk /dev/sdb: 16.3 GB, 16257318912 bytes
256 heads, 9 sectors/track, 13781 cylinders, total 31752576 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xc3072e18
Device Boot Start End Blocks Id System
/dev/sdb1 * 2192 31752575 15875192 c W95 FAT32 (LBA)
ubuntu@ubuntu:~$ sudo mount /dev/sdb1 /mnt
mount: /dev/sdb1 already mounted or /mnt busy
mount: according to mtab, /dev/sdb1 is mounted on /cdrom
ubuntu@ubuntu:~$ sudo mount --bind /dev/ /mnt/dev
mount: mount point /mnt/dev does not exist
ubuntu@ubuntu:~$ sudo mount --bind /proc /mnt/proc
mount: mount point /mnt/proc does not exist
ubuntu@ubuntu:~$ sudo grub-install --root-directory=/mnt/ /dev/sdb1
/usr/sbin/grub-probe: error: cannot find a device for /mnt/boot/grub (is /dev mounted?).