Не загружается grub

 
mint@mint ~ $ 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: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 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: 0x00000000
 
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1   976773167   488386583+  ee  GPT
Partition 1 does not start on physical sector boundary.
 
Disk /dev/sdb: 31.2 GB, 31229607936 bytes
255 heads, 63 sectors/track, 3796 cylinders, total 60995328 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: 0xcad4ebea
 
   Device Boot      Start         End      Blocks   Id  System
/dev/sdb4   *         256    60995327    30497536    c  W95 FAT32 (LBA)
 
mint@mint ~ $ sudo mount /dev/sda4 /mnt
mint@mint ~ $ sudo grub-install --root-directory=/mnt /dev/sda
grub-probe: error: failed to get canonical path of `/cow'.
Installing for i386-pc platform.
grub-install.real: warning: this GPT partition label contains no BIOS Boot Partition; embedding won't be possible.
grub-install.real: warning: Embedding is not possible.  GRUB can only be installed in this setup by using blocklists.  However, blocklists are UNRELIABLE and their use is discouraged..
grub-install.real: error: will not proceed with blocklists.